Top 8 options for designing 3d objects in 3D modeling software
 |  SelfCAD University

The creation and alteration of images is a cut and dried affair in 2D design. In contrast, many CAD programs used for 3D modeling can be a completely different case. The complexity and the sheer number of tools provided in these applications can often lead to total confusion. 

The main focus in 2D design is how appealing the end-product is to the eye. The methods used for its creation are irrelevant. In 3D design, on the other hand, the method used to create or change the model is vital. The reason is that understanding of a good topology structure is one of the most important aspects of 3D design.

Currently, 3D modeling is used in some way in many professional working environments. It does not matter whether you are using it for manufacturing, 3D printing, advertising, or gaming. If you do not focus on how well you use structural topology in this process, the rendering of difficult objects and high poly models will come to haunt you.

SelfCAD is an elite computer program in the 3D stable. It provides a great user-friendly interface, displaying an array of technical and artistic tools for improving the flow of 3D modeling projects. The software allows total control of all aspects of 3D design under a single-user license agreement.

It is important to note that even though SelfCAD is great when it comes to topology, user knowledge of how to utilize each of its tools is important. The absence, or an insufficient user skill, can lead to the creation of flawed structural geometry, which can negatively influence your 3D design.

SelfCAD is a great tool for putting those final touches on your design. A recommended approach during modeling would be to use low-poly objects which allow easy modification while maintaining the underlying structure. 

In addition, SelfCAD offers several of the Geometry Fixing tools, which will fix issues in the topology structure by creating a completely new solid. It’s recommended to use them on a finished design, as it will completely rework the model’s geometry.


About this article 

The focus of this article is to explain the basic concepts that can be applied to any design software. You will be taught about procedures and approaches of best practices in the 3D modeling industry. SelfCAD is the instrument we will use, but the ultimate goal is to prepare you for landing a job in the future.

Our main focus is to cover 3D object creation comprehensively. On occasion, other related 3D modeling protocols may be mentioned, but these will be discussed in greater depth in future articles. 

We have set up a forum where you can view any upcoming news and blog posts. The forum has a two-fold purpose. To keep you informed and to assist us to continuously improve the quality of the material we can provide. 

We invite you to visit the SelfCAD University channel, where you can not only learn about 3D modeling but also use it as a place to post questions and suggestions. We are committed to answering each question and to consider the validity of each suggestion and comment made. 

Before we look at the 8 ways of creating 3D models in a 3D modeling software, we would like to check on a few key concepts in 3D modeling.

 

Geometric primitives vs imported objects

SelfCAD allows you to work with 3D objects of different file formats. It allows you to reuse previously created 3D objects in the same way that Photoshop designers reuse their images and designs. It also gives you access to over 100 000 objects in the MyMiniFactory library. This resource integrates seamlessly with the SelfCAD editor. The software also offers a variety of tools that allow the importing and modification of any solid.

Geometric primitives are different from 3D imported objects as they can be modified using mathematical functions to change their parametric nature. 3D designers have a preference for using geometric primitives to make low-poly 3D objects which are of superior quality. This is understandable, as 3D modeling software can generate optimized topology which is of an exceptionally high standard based on the shape being used.

 

Linear vs circular based Geometric Primitives

Geometric primitives differ in their properties. Some of these shapes have plane related settings associated with their 3D orientation. These include cubes and other planar shapes. As a result, the primitive can be modified regarding its size and number of segments, and 3D transformations may be used to change the volume of the primitive. SelfCAD has several Resolution and editing tools which allow you to ignore many of the original settings by providing options to increase or decrease the poly count.

In contrast, circular shapes in 3D space are completely different. Their appearance and geometry are based on the fact that the number of segments has a direct association with the number of revolutions. When you change the number of segments of the primitive, there is a direct impact on the polygon count, and ultimately on the actual 3D design of the object. The application of the Resolution tool to the shape only affects the face count on each polygon.

The Round Object and Simplify editing tools allow the change of the smoothness of the polygon. If you are looking for the best way to manage the basic primitive smoothness, then circular shape generators are the perfect solution.

Manipulation of sizes is different for circular shapes and planar objects. To change the size of a circular shape, a change in the length of the radius is required. It is important to view this as a new measuring system because the radius of the displayed sphere will be exactly double that of the intended length. On the other hand, changes to planar objects use bounding-box measurement principles.

 

 

You will notice in the above image that the number of quads does not change the appearance of a cube. It is also possible to use different segments for each side of the shape, as displayed in the second row.

On the contrary, the appearance of cylinders differs as their vertical segments change. This is seen in the third row. The last row demonstrates how the manipulation of arc settings can result in the formation of shapes that are not truly closed circles. 

From the two bottom right objects, it is clear that there is a decrease in size as we progress from the bottom to the top of the circular shape. This is as a result of the ability to have different radios set for the top and the bottom of the geometric shape. Similar to the cube illustration, the non-circular horizontal profile demonstrates that the shape is unaffected by the addition of more horizontal segments.

We know that a sphere is always circular regardless of orientation. However, this property results in a shape change when horizontal segments are altered. A phenomenon is clearly illustrated in the above picture.

 

Geometric primitives, irrespective of their shape, can be altered using the same basic principles. The topology of circular shapes relies on the associated mathematical function. As a result, alterations are imposed on primitive design when the settings are changed. On the other hand, plans associated with planar objects makes it possible to use segments to subdivide objects, and then employ these to change the shape.

 

Triangles vs quads

The planar nature of triangles allows you to create this type of geometric shape when the vertices are on the same plane. It also allows for the creation of more sophisticated forms such as a torus knot when employing twisted shapes. Irrational use of planes when working with triangles can result in a non-manifold geometry as an output.    

Triangles are excellent primitive shapes for creating the tops and bottoms of spheres and cylinders, while quads are used for representing all the other surrounding faces. Quads are used in cubes and torus knots. Triangles are extremely useful in the design of other primitive forms and shapes. 

Designers find that the versatility of quads and triangles provides them with excellent tools for creating an array of topological forms. It simply comes down to finding the most suitable combination for their specific requirements.

 

Why does it matter what style and how many faces does it have?

The main reason for using primitives is that they can be molded to suit your specific needs. To perform these procedures correctly, a designer needs to have direct interaction with the topology structure.

Choosing the correct scenario when deforming structures is extremely important as is illustrated in the example above. The lack of faces causes distortion in the deformation of the cube during bending. In contrast, the presence of additional segments allows the bending process to take place without issues. 

The benefits of having a triangular structure on top of a cylinder are emphasized when the cylinder is taken through an angle of 270-degrees. The result is a well-produced rounded staircase.

Our focus will remain on the creation of 3D structures for now. We will produce a new article to discuss the editing and deformation tools which have placed SelfCAD as a top-notch contender in the 3D design industry. 

 

Custom shape generators

SelfCAD comes with a well-rounded 3D Shapes facility. It includes some of the most useful premade shapes such as gears and screws, which can be manipulated to sort your specific requirements, but the most unique of them is the Shape Generator.

The Shape Generator works similarly to other shapes, but it gives you the ability to stack different shapes and forms on top of each other. The software will even ensure that the connection between different shapes in a stack appears smooth. 

 

 

How to create bridges between 3D objects?

SelfCAD has a unique Shape Generator that is optimized for the creation of objects in a layer-based approach, but with that said, the Loft tool is still the preferred method for creating connections, which include objects and forms that have different orientations.

 

 

The illustration demonstrates how the Loft tool is utilized to connect shapes using different settings. This is visible in the two cubes situated at the bottom of the structure, each with a cylinder at the top. 

It is evident that the connecting shape starts rectangular at the top of the cubes and gradually transforms into a circular shape as it interfaces with the cylinder. The right side includes an added twist to the connector.

Then there are also two horizontal connections. The bottom connection includes a negative bevel, while to top one is free of any modifications.

There are many advantages associated with the ability to create transitions between geometric primitives automatically. Compared to manual design it is extremely time-efficient and allows easy transitions between primitive forms, even if they have different orientations.

Many CAD applications offer different ways of creating bridges between objects. In the case of SelfCAD, the entire process is simplified to the point that a single interface is presented, which cuts down on the number of the required tools. This makes for easier learning. A demonstration in the implementation of loft for profiles will be shown soon.

 

Creating 3D geometries using 2D Drawing

The success of any 2D or 3D design relies on the skill with which drawings are incorporated into the workflow. Your professional background is irrelevant. The most important thing is to familiarise yourself with the process involved when transforming a 2d drawing into a 3D object. The factors and tools involved in the process will be covered in detail. Even if you are using a versatile tool such as SelfCAD, there is no substitute for background knowledge.

 

 

The above illustration showcases what a birds-eye view of the process involved in creating a 3D object will look like. It shows the progression from a 2D contour on the left to the final 3D form on the right, including the intermediate 2D surface. All of this takes place on a 2D plane.

 

Extrusion vs Add Thickness

The first step in this process is to create hollow objects with the Add Thickness tool. This will be explained in more detail in blogs with a focus on editing and involves the utilization of extrusion methods to extend faces. SelfCAD allows two approaches to achieve this:

Surface Extrusion results in objects which have sidewalls with an open bottom end. In contrast, closed shapes can be created with the Add Thickness tool.

The backbone of Extrusion lies in the ability to build side connections by moving along a surface. While some CAD programs give users the option to choose between whether to leave the shape open or to add a bottom face, it’s a standard setup in SelfCAD that closes all surfaces. The program simplifies things even further, by making it possible to delete surfaces as required.

Add Thickness and Extrusion have two opposing functions. Use Add Thickness when you need to change a surface into a volume. On the contrary, Extrusion must be used if you need to keep the shape open.

 

The above illustration demonstrates the difference between the application of Add Thickness and Extrusion to a shape. The second image is the result obtained after Add Thickness was applied to the first image on the left, while the third image shows the result of using Extrusion. The last shape was the result of adding wall thickness to image number 3 to create a hollow object. The open shape in the image on the far right may be closed by applying Fill Polygon, which is also used to produce similar results in 3D solids. That’s the beauty of SelfCAD’s reusable tools.    

 

What is a planar design?

The planar nature of the 2D sketch shown above is only apparent when looking at it from a top to bottom perspective, wherein the height of the form is linear. A side view of the same form provides a completely different picture. This influences how designers add detail to the final shape and often results in the use of more than one drawing plane. Some designers prefer an approach where they rotate the final object and work in a single plane. The secret to working on a 2D sketch lies in that the design is planar and that the third dimension or axis is linear. 

 

3D Sketches

The 3D pathfinder found in the Fill Polygon tool makes it a great way of locating 2D surfaces in any 3D profile. Its utilization of constrained triangulation adds to its success as a useful method for converting object profiles. For now, the focus will be on the utilization of triangulation methods on 2D profiles, while best practices will be covered in a later stage. 

 

Solid vs Hollow objects

Triangulation is versatile in that it can be employed to transform solids devoid of any cavities or profiles which contain holes and have multiple paths. Its effectiveness was demonstrated above by using a single solid polygon and a path where the area of the profile was inclosed completely.

 

 

The image of the shape shown above is more sophisticated than the previous one in many aspects. Although it is also planar, it consists of several paths, and a closed polygon chain is used to describe the thickness of the wall in each partition. The wall is also variable in respect of height.

This type of design can be produced by implementing geometric primitives and box modeling techniques. It is interesting that even though box modeling is often used for interior design, some designers still opt for an approach that makes use of drawings, especially when creating shapes with rounded surfaces.

In the drawing displayed above, an identical 3 step approach was used as previously. The front-back plane was used for the profile, which was then transformed further by filling and the addition of thickness. The only difference to the initial example was the drawing plan.

The parts of the design identified for further modification were marked in yellow. These sections were transformed into the final desired shape. Some enhancements were introduced to increase the visual appeal of the design.

 

The order of Extrusion

It is extremely important to pay special attention to the order in which the Extrusion takes place. A non-manifold solid will result if the final two steps of the process were swapped around. We will elaborate on this in another blog.

 

Cutting holes in objects

In both of the previous examples, we have created solid objects free from holes. In the first instance, there was a single path profile from which a solid object was the result. In the second case, multiple Extrusion manipulations were carried out along different paths.

 

 

The picture frames shown above were drawn using the SelfCAD Freehand drawing interface. Only the wall thickness presented any volume, with about 100 holes in the frame walls as well as a central hole.

The automation capability of the Freehand drawing tool allowed us to produce the design in less than a minute. The same can be achieved with 3D Sketch tools by including some extra manipulations. We will elaborate on this soon. 

 

Understanding the drawing Topology structure

We’ve already explored almost all planar drawing and triangulation use cases. Still, without understanding the topology structure, it will be difficult to make sense of them all, and it will be challenging to make the best out of the different available drawing tools.  

 

Constrained Delaunay triangulation

SelfCAD often incorporates the common triangulation protocol known as 2D Constrained Delaunay triangulation, even in Freehand drawing and the Fill Polygon tool. The beauty of this protocol is that it provides methods for dealing with convex and concave polygons. For the present topic, it is good enough to understand what the meaning of "Constrained" is, how it assists in producing high-quality objects, and what are the disadvantages associated with this procedure.

 

What is a Constrained triangulation?

It simply means that the final solid will be created based on the original position and number of vertices that are present. Hence the term "constrained".   

 

How does Constrained triangulation help with design?

By maintaining the position and count of the vertices, it allows the designer to draw shapes within shapes. This is quite useful if there is a requirement for creating a multiplex design. Secondly, it allows designers to merge adjacent planes in the same 3D profile. This feature makes the creation of watertight solids a reality. All of this will be explained in the sketches below.

 

On the left, we have a sophisticated 3D cylindrical profile. There is a custom drawing in the same plane as the bottom circle. The circular top has two lines drawn through the center of the circle which crisscrosses each other.

On the right-hand side, you see the solid we created using the Fill Polygon tool. So far, you see no significant difference from all added parts to the design. It just created slices in the solid that match cuts on the profile. If you use the Resolution tool and set to "0”, it will remove all these extra details because those details don't add value to the cylinder. Take careful note of the following paragraph to see how to use this knowledge in practice.

 

 

The first two objects are duplicates of the same cylinder. They have been turned so that the top and bottom ends of the cylinder are visible, and the profiles of the parts from the solid are now visible as well.

SelfCAD's Inset tool was used to generate distance between the four parts, and to enhance visibility. The shape was manipulated further using different Extrusion techniques and by adding different textures. These procedures are covered in greater detail in articles focussing on modeling and editing.

The Follow Path tool in SelfCAD was used to create a circular mold around the Tabletop, while the software's Stitch and Scoop tools were used to place and round the text in the center. These two procedures will be explained below.

 

How to use Follow Path with profiles?

Follow Path is a versatile tool and can be used when working on a solid. It can extrude shapes along a path in the same way as the Follow Me Tool in Sketchup and can make copies similar to the way AutoCAD utilizes its array command. The Follow Path can operate along various paths on profiles, but it is important to use it skillfully so that you will create solids of acceptable quality.

 

 

In the example represented above, we look at how to use the Follow path tool in combination with the Stitch and Scoop Union tool. Both of these are part of the SelfCAD suite. As we proceed from left to right, a single solid is created using an advanced profile. It is followed by a pattern consisting of a central spiral of lines that intersect the outer circle. The third example demonstrates how with the Follow Path tool we were able to create visually appealing solids by separating the path into two. Finally, the solids were merged using the Stitch and Scoop Union tool.  

 

The Follow Path flow

The Follow Path tool is quite easy to work with. In our scenario here, we have used the small, red shape to trace the profile edges. Simply choose your drawing, select your desired profile, and initialize the Follow Path tool.

 

Duplicated vertices and faces

We used two different techniques for creating a solid used in our examples. Firstly, we produced a solid that covered the whole Sketch. In the second case, the circular part was represented by a single solid. However, each line made a separate solid.

We ran into problems by producing a non-manifold error due to the number of overlapping vertices when the Union boolean tool was used. This was rectified by using the SelfCAD merge tool to merge the inner edge solids. Overlapping vertices were removed by implementing the Remove Duplicates tool. To complete the process we were able to join the inner and outer segments by applying the Union tool. This highlighted a drawback of the boolean tool. It fairs well when dealing with intersections, but comes short when having to contend with overlapping faces and vertices.

 

Boolean operations

Before moving forward, it’s essential to understand the four operations you can do with the intersected shapes:

  1. Union. It is not the same as merging as you keep both objects, the function places them into a single shape by stitching together the topology.

  2. Difference. With this function, you keep one object and remove the part that is intersected. The number of choices increases with the number of available objects for the Difference. You can decide on which object to keep and on which one to discard.

  3. Intersection. Both shapes are retained, except the part that is intersected.

  4. Exclusion. Both shapes are removed, except the part that is intersected.

 

Boolean is the scientific name used to describe the four operations above. Some software reuses the same names for these tools, while some have a custom, more intuitive naming convention. SelfCAD calls Boolean operations “Stitch & Scoop” and names each of the four operations within the tool with the common names, as they seem to be intuitive enough. 

 

The above image illustrates the available boolean operations for two intersecting objects. Most 3d modeling applications tend to reserve Stitch and Scoop for intersected volumes, and offer Trim and Brake commands for profiles and surface cutting. 

It is well known that boolean operations can result in errors when they are used to build solids for non-manifold objects. These include overlapping faces and vertices. The problem is that these functions try to rebuild solids from the ground up, and result in the formation of nonsensical topology structures.

SelfCAD was built from the ground up, and it developed many of the algorithms themselves but is also mindful of the dangers of reinventing the wheel. As a result, it also utilizes many of the proven, open-source algorithms.

In Boolean, SelfCAD used the same libraries that most CAD software use, including the likes of Blender. Despite being an online 3d modeling software, SelfCAD uses WebAssembly to cross-compile the C++ library and work for the browser. So it is evident that all software faces the same issues. You only need to have a basic understanding of what they can and can’t do. We hope to elaborate on it in Tips and Tricks for boolean in the Geometry fixing blogs. 

When it comes to 2D sketches, you get much more flexibility with topology structures when using the Trim and Brake commands. As a result, those features became a standard. However, SelfCAD managed to simplify even them, as will be described below. 

 

Trim vs Boolean

The common thing in Boolean and Trim operations is how they use the intersection to eliminate parts of objects. However, the logic on which these functions are built is completely different.

Boolean has 4 predefined operations for cutting out volumes. This means you need to have a minimum of two shapes, and that they have to be Manifolds as well. These operators are only viable when you have selected intersecting volumes.

Contrary to Boolean, Trim is not bound or limited by volume. The function allows the trimming of open paths, pats from single profiles, and also intersecting tangent lines.

Some of the Trim options are covered in the sketch above. The first example demonstrates a scenario where you have a square with two diagonals. The second example is more complex, as it consists of a rectangle with an arc at the top. Within the rectangle, a spline is drawn from the bottom left vertex and extends to the bottom right corner.

 

How to find the center of a drawing?

In the example demonstrated above, the center point was not calculated. This is an important part of drawing flow. Fortunately, SelfCAD automatically shows all center points, and it automatically adds an intersection point to the center of each line, arc, etc. This simplifies the process of connecting shapes predestined to be trimmed.

 

How does Sketch Trimming command works?

A Trim function can be found in most CAD programs. Activation of this function will allow you to select parts of the topology that you want to be removed. This process is greatly simplified in SelfCAD where intersecting edges are split automatically, and as a user, you have to simply select any segment you want to remove and delete it.

The above video clip demonstrates how easy it is to trim in SelfCAD. Just be mindful that SelfCAD only adds additional vertices either when drawn as a single profile or when merged.

 

How to brake intersecting edges?

Braking is similar to Trimming in that a vertex is added at intersections. The main difference is that it keeps all lines. This makes it possible to triangulate the sketch to produce excellent topology which can be edited later as required.

SelfCAD automatically breaks all intersections within a single profile. As a result, additional tools for trimming and breaking are not required. The software allows even greater flexibility when it comes to the selection of objects or parts of structures. We will elaborate on this, in the following blogs.

 

Introduction to Freehand Drawing

The Freehand drawing tool found in SelfCAD sets it apart from many other CAD programs. It is an interactive 2D tool drawing tool with an implemented, live boolean tool, which offers a unique, Freehand Drawing Brush with adjustable settings for thickness and style.

In the above picture, the entire drawing was created just two easy steps. The entire process was completed by using the Freehand brush with round style, and with a thickness setting of 40.

Erase Mode was used with a brush thickness setting of 20. We were able to create a smooth and accurate drawing by utilizing snap to grid, and by drawing along the same path as before.

Compared with other CAD drawing tools, this worked like a charm. Using traditional software required the manual offset of brush thickness and rounding of the corners of the rectangle. Also, the drawing of the inner pattern would have been impeded.

The above video clip shows how SelfCAD automatically simplifies the entire drawing process. During the video, three circles are drawn followed by the addition of connecting pieces using the Brush. SelfCAD automatically identified and marked a closed-hole in red as a sign that it needed to be subtracted from the design.

This works well when close shapes are drawn and you do not add detail to pre-existing forms. If there is the need to subtract directly from a shape, then it is best to switch over to the erase mode.

In the video, the designer is seen cutting parts from a seat creating holes in the wheels. Note that the designer wanted to cut sections from a shape that was created previously. As a result, there was a chance to use the Erase mode. Once the configuration button was clicked and the solid was created, SelfCAD finalized the object and completed the drawing.

 

How to convert a Freehand drawing into a 3D solid?

The Freehand drawing aims to create 3D objects quickly, and so clicking on the confirmation icon will complete the sketch by converting it into a solid with a height of 20. You can change the height in the settings or scale the object later, but as long as there is some height value, the software will create a solid upon finalization. However, if you set the height value to "0",  the software will create a profile as a result. This will be covered a bit later.

 

Interactive vs isolated tools

SelfCAD has two types of tools. Isolated tools include 3D primitive generators and Freehand drawing. Interactive tools include 3D Transformations, Deformations, and 3D sketch. The main difference between these tools is in the way they are handled by the editor. Isolated tools cannot be kept open while working on another feature, while interactive tools allow you to have more than one tool active at any given time.

Tools that are heavily involved in the creation of geometric structures are generally isolated, while tools with less geometric processing are usually interactive.

Freehand drawing allows you to work on a sketch before it is finalized as a solid. Compared with other CAD packages, SelfCAD has been able to accomplish the development of interactive boolean operators which are smooth but have continued to keep freehand drawing as an isolated tool. The drawings have an additional option called "Move Points" which may be used to edit the sketch. 

 

Moving a 3D Sketch to Freehand drawing

In the Freehand drawing, it is possible to drag and drop any object as long as it has less than 100K faces into the scene, and SelfCAD will flatten it, and convert it into a profile. The same applies to solids, profiles, and surfaces alike.  

Another option for converting a solid, profile, or surface image in the scene graph is by double-clicking the object. This is a great way of making sure that the converted object is at the intended location where you would like it to be.

In addition to drawing, drag and drop functionality is also active in erase modes. The same capabilities are available as in the drawing workspace. It also offers a useful way of testing 3D primitives without actually having to sketch the form.

 

3D Sketch

The 3D sketch is similar to what you have in most professional 3D CAD software. The main difference between the 3D Sketch and Freehand Drawing is:

  • It creates a profile instead of a solid

  • 3D Sketch is an interactive tool

  • It is possible to draw 3D sketches

  • You can sketch most elements such as between objects and other drawings, including drawing directly on objects

 

What is a profile?

It is a Sketch that does not have any faces to qualify as a solid is a profile. Similar to a human profile, profiles can be made up of any drawing primitives such as lines, arcs, splines, etc. Such a profile can occur as 2D or 3D.

 

What can I do with a Sketch?

The main purpose of sketching is to create profiles that can be converted into a 3D solid later. In some cases, some users use sketches to set up measurement guides to assist them with creating or modifying other 3D objects.

 

How to offset and edit a Sketch?

All standard solid tools may be used for the creation of profiles and surfaces. The advantage is that this approach allows you to modify and extend solids without duplication. It also provides a common area for working with sketches.

 

 

The above is an example of just a few commonly used features. You can also use Extrusion, Simplify, Resolution, etc. One of the unique tools that engineers use a lot is the Add Details tool, which is handy for creating interior designs, etc. For a more detailed overview of how to work with profiles, see the Working-With-Profiles overview. The add details tool has been updated recently, adding even more flexibility.

 

How to convert a Sketch into a solid?

A Sketch can be converted into a polygon solid by using one of the following methods provided by SelfCAD:

  1. Fill polygon 

  2. Loft 

  3. Revolve 

  4. Follow Path

Each option offers different pros and cons. You should be able to find a suitable solution for your specific requirements.

 

What is Fill Polygon and how to use it?

Fill Polygon as an extremely versatile tool that can be used in many scenarios on the SelfCAD platform. Its functionality is based on the triangulation of polygons. The function may be used on solids, profiles, and selected objects and regions.

Regional selection will be covered in greater detail in the 3D modeling and editing article. In short, it is used for working on sub-elements of a solid. The selected regions can be subjected to the triangulation of polygons.

 

How to use a 2D triangulation to create a 3D Solid?

2D polygons are the main elements of polygon solids and it is often difficult to find the correct 2D polygons for 2D triangulation. This becomes more prevalent the more complex the shape is. A method employing a 3D pathfinding algorithm is often employed in this regard. It is best to triangulate one surface first, and then apply Extrusion or Add Thickness to complete the other sides of the polygon solid.

Filling and Adding Thickness only work on planar surfaces. 3D Sketching, on the other hand,  may assist with the creation of intricate and organic forms.

SelfCAD has a 3D pathfinder to locate the correct polygons for triangulation. Compared to other CAD software, where you might have to find each polygon manually and then triangulate each of them separately.

To implement this tool correctly, some basic understanding of polygon structure is required.

 

This example was already shown a bit earlier. The first step in the flow is to draw a circle, which is followed by using arcs to form the internal shape. 

The next stage of the procedure was to form the cylindrical shape without including the internal drawing. This was done by applying extrusion to the circle instead of drawing the vertical lines manually.

This was followed by the addition of cross lines to complete the shape and to ensure that all the polygons have what is required to make it a closed shape. A polygon count of about 20 is what is usually required. 

 

Filling parts separately

The polygon triangulation protocol used will be based on the constrained triangulation algorithm. The restrictions placed on the position and number of vertices in this model makes it possible to include the Filling and Merging of adjacent parts.

Depending on whether the surfaces share the same edges or not, you might be able to fill them separately and merge them safely in this way. Then it is a simple procedure of removing the duplicates to generate a manifold solid. This is the same procedure employed by many CAD platforms when dealing with complex shapes. The same approach might be applicable if you use SelfCAD, where 3D pathfinding might not always produce the accuracy you want.

 

How does Fill Polygons work on open paths?

SelfCAD will attempt to close open paths if it can find a viable solution. The advantage is that this software can often provide solutions to scenarios other CAD programs will simply fail in.  This is possible by having the ability to provide results based on a managed triangulation output.

 

Polygon orientation-flipped normals

The difference in orientation of each polygonal solid can impact on which side points towards the camera view. The triangulation could flip this order in scenarios involving complex shapes. Fortunately, it is not a major drawback as you will just need to Flip the polygons so that they have the desired orientation.

It is in this regard where SelfCAD is an extremely useful set of tools for analysis. The Backface culling feature of the software detects flipped faces and this will engage its Flip Normals tool which will reorientate the polygons. This will be covered in greater detail in our articles focussing on topology fixing.

 

Other tools used to create 3D Objects

We will now deal with the two outstanding methods for solid creation. Both Loft and Revolve use contours but have completely different flow and topology structures. To start, we will weigh up those methods with each other.

 

Revolve and Loft

The Loft is extremely flexible in that it allows for the creation of organic shapes, but on the downside, it often requires the use of more than one profile. In comparison, Revolve works on a single profile, but its analysis is limited to the creation of circular shapes.

 

How to use Revolve?

Revolve can work on open and close paths and can use a profile to extrude and make the extra geometric structures it requires by utilizing a circular pattern. On top of that, SelfCAD will provide options to select another line segment manually, upon which it will attempt to find the rotation pivot.

 

The software will give a clear indication if there is a problem with the orientation of a profile. You will simply have to check or uncheck the Flips Normals box as required.

 

Revolve retrieves all geometry details from the sketch drawing. This simplifies matters a great deal in that if the final object must be Split, it is simply a process of adding a vertex to divide the profile. The final solid will be updated with the appropriate topology structure. The vertex can be added by using the Add Details tool or by modifying the drawing. This almost mimics the constrained triangulation that was discussed earlier.

 

How to convert Arcs and Splines into Segments?

If you need to select a curve or spline as the revolve rotation axis, you will first need to convert them into edges. That’s the standard in most CAD software. You can convert splines into line segments using the resolution tool. Most tools in the Modify section will also convert arcs and splines into edges. 

 

How to use Loft?

Loft uses a weighted function to interpolate the geometry between all segments, and it may add more vertices, as needed. The Loft feature is one of the most used tools for creating organic shapes. We already mentioned above about the optional bevel and twisting effects in SelfCAD’s Loft tool. Still, the core features are much more potent than these. 

 

 

In the above video, it is demonstrated how a designer created a Corona Mask with technical drawings and guides using the Loft tool. Its precision makes it an excellent tool for designers and mechanical engineers for the creation of organic shapes.



 

 

The above example illustrates the use of 3D twisted profiles, which is not limited to planar surfaces such as the polygon tool feature.

 

Triangulation vs Loft

One of the advantages of Loft over Triangulation is that Loft can freely interpolate between segments making it an easy way to study very complex surfaces. In comparison, triangulation can be utilized only after many inner lines have been added to divide the surface into 2D polygon segments.

 

Revolve vs Loft

Revolve offers better options for studying complex circular shapes by creating a single profile. It also allows for the creation of a circular pattern topology structure similar to circular primitives. On the other hand, Loft can create any organic shape by using contours and plans to create planar objects. This makes a huge difference in the creation of topology structures. With all of this said, it still depends on what you are trying to design.

 

Technical Drawing

It is possible to add measurements using a text box. SelfCAD has a great array of tools for Measurement and drawing Guides, which can compete with many other major players in the industry.

The Guides can be used to enter appropriate distances and angular measurements. Drawings also have the option that they can snap to the grid which is one way of ensuring the accuracy of measurements in your creations.

The Measurements tool, on the other hand, does not place any guides on the viewport, as it’s just showing the measurements in the text box in the bottom left corner of the screen. It allows you to get a precise unit distance between two existing drawing points or an angle between three given points. 

The most interesting feature of the Measurement tool is that you can also change the angle and length from any selected measurement, which will automatically move and adjust the related points. You can even set how to reposition the points. You can choose from the starting point, endpoint, or both, and it will adjust the vertices accordingly. 

 

From the image shown above, we can see how the software deals with and displays both measurements between points, as well as the angles between lines and line segments.


 

Image to 3D

SelfCAD also offers an Image-To-3D tool as another way to create 3D objects. Although it is not a great way for optimized topology design, it’s an excellent tool for making Logo Designs for Business.  It’s an exceptional tool for designs that do not need many modifications, such as this Ivy Vase, and its primary use case is for making a nice Lithophane.

 

In conclusion 

SelfCAD offers a great platform for creating and designing 3D objects. It has an easy and user-friendly interface which makes it perfect for beginners, and its diverse toolset competes with any of the more costly CAD programs on the market. On top of that, thanks to its intuitive design, SelfCAD has the lowest learning curve when compared to other CAD software, and its intuitive design flow has set it as a firm favorite amongst designers, both beginners, and professionals alike.

 


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