UPDATED

3D Design Intent
BricsCAD Platinum determines automatically what you were probably intending to design. This is
known as design intent. When design intent is turned on, BricsCAD recognizes parts of 3D entities
that ought to be edited together automatically. This is similar to the actions of another MCAD program
known as Solid Edge, where the function is named “Live Rules.” AutoCAD does not provide
design intent.
Consider an object with several holes of the same size. When design intent is running, it recognizes
that they all have the same diameter. When you change the diameter of one of the holes, BricsCAD
changes the diameters of the others automatically. This is why design intent is also known as “automatic
3D geometry constraints recognition.”
Unlike constraints, you cannot, unfortunately, apply design intent to specific areas of a model:
design intent is universal. You can choose, however, which aspects of design intent you want operating.
For instance, you can have BricsCAD recognize planes that are just parallel, coincident, or
perpendicular to each other.
I find it convenient to toggle settings through the Design Intent toolbar. Click the big red X to turn
off design intent.
Design Intent toolbar toggles settings
Design intent settings are toggled through the dmRecognize variable; see table below. Setting the
value negative turns off design intent, but retains the former value.
dmRecognize Description On by Default
0 All off
1 Tangent surfaces of planes, cylinders, and cones
2 Coincident planes •
4 Parallel planes •
8 Perpendicular planes
16 Cylinders perpendicular to planes
32 Coaxial surfaces of cylinders and cones •
64 Equal radius on cylinders (or holes) and spheres •
negative value
All off, yet retains value of the previous setting
There is a limitation to automatic feature recognition that’s common to all CAD systems: the engine
works only with 3D solids that it recognizes. For BricsCAD, this means that design intent works with
simple shapes — planes (flat faces), cylinders, cones, spheres — but not with bodies of arbitrary
shape. The simple shapes can, however, be part of a more complex body.
6 Working in 3D 197