Brep Faster Holes? using AddTrimCurve?

Scripting
1

I have a set of closed co-planar curves. One is the “outside” and the reset are “holes” & I know which.
I need to make a Brep in order to render them.

I have been using Brep.CreatePlanarBreps(crvs, 0.001);
However this is too slow for use in our DisplayConduit (where i have hundreds of such sets of curves).

Since I know which is the outer and which are the inner i thought it might be faster if I could construct the Brep more manually using Brep.CreateTrimmedPlane & then adding the holes manually using
Brep.AddTrimCurve method (rhino3d.com)

however no hole is created :frowning:

What is the correct way to use this method?
Is there a faster approach?

	var outer = (new Circle(Plane.WorldXY, Point3d.Origin, 50)).ToNurbsCurve();
	var inner = (new Circle(Plane.WorldXY, Point3d.Origin, 25)).ToNurbsCurve();
	var brep = Brep.CreateTrimmedPlane(Plane.WorldXY, outer);
	brep.AddTrimCurve(inner);
2

did you see those infos / samples ?

1 Like
3

Thanks @Tom_P yeah I’d seen those samples - was hoping to find a mechamism without having to dig into the minutia - that sample takes 600 lines to build a brep :scream:

The last post in that thread was handy, this approach does indeed make the hole

var outer = (new Circle(Plane.WorldXY, Point3d.Origin, 50)).ToNurbsCurve();
var inner = (new Circle(Plane.WorldXY, Point3d.Origin, 25)).ToNurbsCurve();
var brep = Brep.CreateTrimmedPlane(Plane.WorldXY, outer);
brep.Loops.AddPlanarFaceLoop(0, BrepLoopType.Inner, new[] { inner });

That approach takes my Display Conduit from 14000ms to 373ms to build the Breps so quite an improvement. :smile: This is on 1000 curves.

4

Just for interest this is what I’m testing on - nested gaskets ready for laser cutting.

image
image1595×1581 1.11 MB

The DisplayConduit takes 600ms to load - 200ms for our containment test routine & 400ms to create the Breps & bounding box.

Would love to make it faster :slight_smile:

5

just guessing:

track the transformations of same parts.
create a single brep.
create a quite rough mesh
copy and transform the mesh

maybe a hatch is faster then a brep ?

6

Hi @david.birch.uk,

You might trying add each planar curve as a planar face loop.

test_planar_loops.py (2.0 KB)

– Dale

7

Thanks @dale

Yeah that worked nicely - 14000ms to 400ms,

@Tom_P Good idea i’ll have to see if hatches are faster

For now I parallelized the Brep creation and dropped my test case from 400ms to 75ms, probably good enough for now - two orders of magnitude improvement is enough for one days work! :laughing: