I am making a cutters library that will be used thousands of times with BooleanDiff. When Rhino tries to do the NURBS math for intersections, what type of surface is better? Is a degree 3/20 control point surface faster than a degree 8/9 control point surface?
When I say better, is speed and error rate one is the same? If I had to choose, I would like the least likely to fail option.
Here is an example of 3 options I have for a cutter:
BooleanDiffBestPractice.3dm (221.5 KB)
Perhaps you should wait for an official response but…
Myself, I like making everything with as few nodes as possible.
I try to avoid Booleans with angles that run near edges nearly parallel to edges, like subtracting a cylinder from the inside edge of cube, with features like this:
Which causes issues with floating point; an approximation has to be made somewhere.
For this reason, I routinely make subtraction tools parts that overshoot the edges.
~
I usually give my Boolean tools a special color and material. Mine are transparent orange, as in construction. That way they are not mistaken for positive geometry.
With the geometry you’re showing in your first post, I would make all the objects from trimmed or untrimmed planar surfaces - as simple as possible, degree 1 x 1. That will be the simplest geometry to intersect. After that, it will of course depend on the geometry you’re intersecting with.
–Mitch
That was a simplified example of what my cutter actually looks like. In practice, I flare the ends and strive for tangency in the center.
I imagine all the degree 1 planar math is quite simple and bulletproof, but that would cause an error rate during casting. I get rid of any hard edges in the model and if I need them, hand cut them back into the finished part.
Alignment Points make a nice addition to anything you need to position repeatably : )
Eric, can you post or send me a non-simplified example or two?
-Pascal