DraftSight 3D Modeling Part 2 – Creating Solid Bodies

Article by Mike Walloch, CSWE updated June 13, 2023

Article

DraftSight Premium, Enterprise Plus, and Mechanical offer users the ability to create non-parametric 3D models. Non-parametric models, often known as ‘dumb solids’ lack a feature history. Users of parametric systems like SOLIDWORKS or CATIA may have encountered them by importing models from neutral CAD formats, like Parasolid, STEP, and IGES. Parametric CAD applications have tools for working with these featureless imported bodies, but don’t build such models from the ground up. So, this method of modeling is unfamiliar territory for most of today’s CAD users. But it’s easy to learn and is an excellent tool for many use cases.

For more information about parametric vs non-parametric Boolean modeling, check out the blog Can You 3D Model in DraftSight?

For information about navigating 3D space and changing view settings in DraftSight, refer to DraftSight 3D Modeling Part 1: Views and 3D Navigation

The Basics of Boolean Modeling

The core of Boolean modeling is simple. Think of it like working with clay. You start by forming a lump of material in a basic shape. Then you just add or remove material as needed. Once you’re happy with the shape, you’re done. For example, you could create a solid entity to represent a mounting plate. Then you could create several cylinders where the mounting holes need to be. Then you’d subtract the cylinders from the plate, resulting in a single solid entity with holes, as shown in the progression below.

Note the plate and the cylinders were on different layers with different colors assigned before the cylinders were subtracted from the plate. The final inside surfaces of the holes are part of the blue plate entity, but retained the color of the cylinders which created them. Geometrically this makes no difference. But you could use the EDITSOLID command to match the color of those faces to the new layer. Or just make sure the cylinders are on the same layer as the plate before subtracting them.

Creating 3D Entities

The ‘Home’ tab of the ‘3D Modeling’ workspace ribbon menu provides easy access to the commands we need to create and modify 3D bodies. The ‘Modeling’ section contains tools for creating 3D entities, either from scratch or from existing 2D entities. The tools in the ‘Solid Editing’ section allow us to modify existing 3D entities. The tools in the ‘Mesh’ section are for mesh modeling, an alternative method to solid modeling.

draftsight solid editing tool

You can start a new model one of two ways. The first method is to start by creating a basic 3D entity using one of the commands in the first two flyouts of the ‘Modeling’ section of the ‘Home’ tab. Options include boxes, pyramids, wedges, planar surfaces, cones, cylinders, spheres, and tori.

 

3D modeling in DraftSight creating solid bodies 3D modeling in DraftSight creating solid bodies

Below is an example of a 3D solid created with the TORUS command. Tori are often called donuts, for rather obvious reasons.

tori model

The second method is to start by drawing profiles using normal 2D entities, such as lines, arcs, and circles. This allows you to create whatever profile you want to serve as the base of your new model. Then you can use one of several commands to extrude that profile into a 3D entity.

drawing profile

In the third flyout in the ‘Modeling’ section of the ‘Home’ tab, SOLIDWORKS users will see such familiar commands as EXTRUDE, LOFT, REVOLVE, and SWEEP. The POLYSOLID command is similar to a thin extrude. The PUSHPULL command makes it easy to use 2D entities to create 3D entities, either solids or surfaces depending on what you select. It can also modify existing solid entities by dragging faces. For detailed information on what each of these commands does, consult the DraftSight Help documentation.

extrude loft revolve features

If you have created a 2D profile using separate entities, you will often need to use the WELD command to turn the entire profile into a single polyline entity before extruding it. Otherwise, each separate 2D entity may result in a separate surface entity being created, instead of a single solid body. The examples below demonstrate the result of an EXTRUDE command on a profile made of lines and arcs on the left, and on a profile which has been welded into a single polyline on the right. Interestingly, the PUSHPULL command produces the result on the right in either case.

extrude command on profile of lines to create solid bodies

Making Complex Bodies

Once you have some basic solid bodies to work with, that’s when Boolean operations come into play. The UNION, SUBTRACT, and INTERSECT commands allow you to combine existing bodies in different ways. The UNION command adds existing bodies together. The SUBTRACT command removes one or more bodies from another body. The INTERSECT Command merges two or more overlapping bodies into a single body matching their shared volume.

To create the model shown below I started with a rectangular block and a cone created from the BOX and CONE commands respectively, and merged them into a single entity with the UNION command. TORUS and CYLINDER commands created bodies which I then removed from the main body with the SUBTRACT command, resulting in a through hole and groove in the cone. FILLETEDGES, CHAMFEREDGES, OFFSETEDGES, and a few other commands tweaked the main body.

created using block and cone commands

Conclusion

Basic 3D entities are the foundation of modeling in DraftSight. In some cases, such as a representation of a printed circuit board, a shim, or a washer, a simple extrusion may be all you need. But in most cases, you’ll need to create and edit several solid bodies, perform Boolean operations on them, and make other tweaks before your model is finished. We’ll look more closely at the tools needed to do all this in Part 3 of this series.

Related Links

Find Related Content by TAG:

Mike Walloch, CSWE

Mike Walloch is a Certified SOLIDWORKS Expert (CSWE) and works as a Process & Training Consultant at TriMech