What Is Direct Modelling in BricsCAD?
Quick answer: Direct modelling works much like sculpting on screen: you start with a base volume and detail it by adding, removing, and deforming geometry, all dynamically and interactively. Unlike history-based modelling, the order features were created in doesn’t matter.
The Sculpting Approach
Just as a sculptor starts with a lump of clay, stone, or wood, direct modelling starts with a base volume that you shape further. Every operation runs dynamically, showing its intermediate result as you move the mouse, and you choose whether to define dimensions intuitively or by typing exact values. Since there’s no underlying feature history to respect, the order you perform operations in doesn’t constrain you the way it would in history-based modelling.
Preserving Design Intent
Direct modelling still gives you parametric control, just through a different mechanism. 3D dimensional constraints, Distance, Radius, and Angle, applied to faces and edges let you change a model’s configuration or scale simply by adjusting a constraint’s value. Geometric constraints, Coincident, Tangent, Parallel, and others, define how those changes actually propagate through the geometry. You don’t need to define every geometric constraint by hand either, most get recognized automatically through Design Intent Recognition options.
Using the Quad for Direct Editing
Direct editing operations are easy to apply through the Quad cursor menu, which offers operations based on whatever entity or selection is currently active, alongside standard solid editing operations like copy, union, and subtract.
What Direct Modelling Applies To
Any ACIS solid geometry, whether created natively in BricsCAD or imported. With the separately licensed Communicator for BricsCAD add-on installed, IMPORT supports all major 3D model formats, both industry-standard and proprietary, the same STEP, IGES, CATIA, SolidWorks, Parasolid, and other formats covered on the file types dictionary page.
Controlling What Happens to Source Entities
DELOBJ decides what happens to the entities that defined an operation once it’s complete:
| Value | Result |
|---|---|
| 0 | Retains defining entities |
| 1 | Deletes profile entities; retains paths and guide curves |
| 2 | Deletes all defining entities |
| -1 | Prompts whether to delete profile entities; retains paths and guide curves |
| -2 | Prompts whether to delete all defining entities |
Frequently Asked Questions
Does the order I perform direct modelling operations in matter? No, unlike history-based modelling, there’s no feature history to respect, so operation order doesn’t constrain you.
Do I have to manually define every geometric constraint for design intent to work? No, most get recognized automatically through Design Intent Recognition, you don’t need to set every one by hand.
Can I use direct modelling on solids imported from other CAD systems? Yes, it applies to any ACIS solid geometry, whether created in BricsCAD or imported, including formats supported through the Communicator for BricsCAD add-on.
How do I control whether the original entities get deleted after a direct modelling operation? Set DELOBJ, which ranges from always retaining them, to always deleting them, to prompting you each time.