Our journey continues as I transition from AutoCAD® to BricsCAD. If you’re joining me as a former AutoCAD user, you probably think BricsCAD is a lot like AutoCAD. And it is, in many ways. You can use most of the same commands and workflows that you’re familiar with from your AutoCAD experience. But, there are some differences, including Direct Modeling.

BricsCAD offers intuitive direct modeling functionality for editing ACIS solid and surface geometry. You’ll find most of these tools in the Quad as well as in the Direct Modeling menu and toolbar. If you prefer to enter commands on the Command line, start by typing DM for a list of direct modeling commands.

Direct Modeling Tools

All the direct modeling operations are interactive. And, the result of the operation displays dynamically as you move the mouse. You can apply direct modeling operations to all ACIS solids, whether you create them in BricsCAD or import them from other modeling applications. And, you can combine direct modeling with regular solid modeling operations, including the ones we explored in previous posts.


The PushPull tool (DMPUSHPULL command) adds or removes volume from a solid by moving the highlighted face. If you drag the faces out from the model, it adds volume. If you push into the model, it subtracts. It can replace the two-step process of traditional 3D editing tools that requires you to first extrude a volume and then subtract it. You can even multiple faces on different planes to combine many operations into one.

Direct Modeling Push/Pull

PushPull understands the relevance of adjacent faces and behaves accordingly.

Direct Modeling Push/Pull


The direct modeling Move tool (DMMOVE command) lets you move solids, faces or edges of a solid, or insertion by specifying a base point and second point (vector). You can produce significantly different results, even specifying the same movement vector, depending what is selected.

In the following example, the selected edge moves straight up the Z-axis to the top of the model.

Direct Modeling Move Edge

The same basepoint and second point is specified to define the movement vector in the following example. However, the face, instead of the edge, is selected.

Direct Modeling Move Face

If you select the entire entity DMMOVE behaves like the traditional MOVE command.

Direct Modeling Move entity


The direct modeling Rotate tool (DMROTATE command) rotates a face or solid around an axis. In the image below, the selected face rotates around its left edge at a specified angle.

Direct Modeling Rotate

You can achieve similar results if you select the right edge of the face and move it vertically using the direct modeling Move tool. Selecting the most appropriate direct modeling tool often depends on what you know. In the example above, you might know the slope angle but not the distance you need to raise the right edge.


The direct modeling Extrude tool (DMEXTRUDE command) creates 3D solids or 3D surfaces by extruding closed 2D entities, faces of 3D solids, regions or closed boundaries. It can add or remove volume if you pull it away or push it into a solid.

Direct Modeling Extrude


The direct modeling Revolve tool (DMREVOLVE) creates 3D solids by revolving closed 2D entities, faces of solids, or regions about an axis. It can add or remove volume if you pull it away or push it into a solid.

Direct Modeling Revolve


The direct modeling Thicken tool (DMTHICKEN command) creates 3D solids by adding thickness to surfaces, faces of 3D solids, and regions. In the following example it behaves similar to DMEXTRUDE when selecting the face of a solid. However, instead of adding or removing volume to the solid, DMTHICKEN creates a new, separate solid.

Direct Modeling Thicken

DMTHICKEN even allows you to add thickness to wireframe entities including lines, polylines, circles, ellipses, arcs, helices, and splines.

Direct Modeling Thicken wireframe entities


The direct modeling Fillet tool (DMFILLET command) creates a smooth fillet between adjacent faces that share a sharp edge. If you select adjacent edges, it automatically blends the fillets where they intersect.

Direct Modeling Fillet


The direct modeling Chamfer tool (DMCHAMFER command) creates an equidistant chamfer between adjacent faces that share a sharp edge. If you select adjacent edges, it automatically blends the chamfers where they intersect.

Direct Modeling Chamfer


The direct modeling Twist tool (DMTWIST) is one of my favorite discoveries so far on my BricsCAD Journey. It modifies a 3D solid, surface or region by twisting it along a specified axis. You specify the start and end of the twist and the angle through which you want to twist. An additional option allows you to control the continuity between the twisted and untwisted parts of the solid.

Direct Modeling Twist

There’s so much you can do with Twist. And, it’s fast and FUN to use! But, don’t tell your boss! It’s better job security if they think you struggled for days trying to figure out how to solve these design challenges with traditional modeling tools!

Direct Modeling Twist examples

If you don’t believe how easy it is, check out this video to see Twist in action!

Direct Modeling Utilities

In addition to the direct modeling tools I described above, Bricsys offers several tools to help you fix models if you run into problems. You can refer to the Help system for more details.


The Simplify tool (DMSIMPLIFY command) removes unnecessary edges and vertices, merges seam edges, and replaces the geometry of faces and edges by analytic surfaces and curves, if possible within the user-specified tolerance.

It’s good practice to run Simplify on any 3D solid geometry you import from other applications.


The Stitch tool (DMSTITCH command) converts a set of region and surface entities that bound a watertight area to a 3d solid.


The Audit tool (DMAUDIT) Fixes inconsistencies in 3d geometry supported by ACIS kernel (3D solids, surfaces).

It’s good practice to run Audit on 3D geometry you import from other applications.

What Next?

The 3D modeling tools in BricsCAD are making my transition from AutoCAD to BricsCAD incredibly easy. To ensure I fully understand the tools, I am modeling my home from scratch. I started with solid primitives and then used the extensive set of editing tools to complete the exterior. If it’s this easy with BricsCAD Pro, I can’t wait until we get to Platinum with the BIM module! But, we’ll have to wait because there’s still plenty more to explore with BricsCAD Pro.

Direct Modeling House

The next stop on our journey introduces us to the section tools. They’ll come in handy for modeling the interior!

Looking Back

If you missed the previous tours on our BricsCAD Journey, it’s never too late to catch up! First, learn about functionality in the BricsCAD Classic Edition. Then, continue to the Pro Edition. Everything you learn about Classic also applies to Pro!