Hi all, I have a scene with many surfaces and I want to do some ray intersections (no reflexion, just direct). In order to solve the untrimmed geometry problem, I was about to use the pointOnFace method proposed on many other posts. But I couldn’t find how to get the hit geometry from the RayShoot…

So far, I could momentarily solve my problem by writing the following function. The principle is the following : for each ray, the program go through all the input geometry to see on which one arrived the ray. then it checks if the ray arrived inside the trimmed geometry. public Point3d Fu…

Hi @TomTom , I do not understand what do you mean by “selecting” the object before ray shooting. Can you please attach some code ? Eventually just the command line. So far I couldn’t find any way to get the hit geometry directly from the rayshooting option. Althought it is the most obvious way to pr…

Hi @em.rudelle , Internally, we know which Brep face was hit. RhinoCommon just needs to return this. I’ve created an issue so we can provide this in the future. https://mcneel.myjetbrains.com/youtrack/issue/RH-57098 – Dale

Sorry but I’m very confused with what I should do with this ObjectTable. According to Dale’s answer, it looks like the rayshoot method doesn’t output the hit geometry in any way. I’m not sure you can get it by “selecting the object before doing a rayshoot”, I’m not even sure if that makes any sense.…

Thanks for the update ! Although we cannot expect our users to run on the last WIP version. As a matter of fact I finally wrote a code that computes this RayShoot very fast, and it is compatible with Rhino6. I’m sharing it here, in case someone read this and has the same problem later on. public P…

Where exactly did you optimise something? Don’t get me wrong, I really like to know, but I don’t understand where any optimisation was applyied here. The same confusion I had with your PM.

Hi again @TomTom , The algorithm is not the same since I’m doing intersection on geometry myself instead of using the rayshoot method. On the first algorithm I was checking (among all surfaces) to which surface belonged the result point. Whereas now I have it straight away. If we assume that in t…

I mean a simple optimisation is to filter out the physical intersections by using mathematical ones at first, so that you reduce computation time. In my example you see how I created 30001 objects. I simply added a bounding box intersection before doing the physical one, because I don’t need to d…

Hi @TomTom , Your help is much appreciated, thank you. I don’t have so many Breps to intersect with, but it already halved the computation time for my whole recognition process. Yes I’m not very familiar with computation and optimization, so I’m glad you proposed your kind help.

Ray Intersection - Getting the hit geometry

Rhino Developer

brian (Brian Gillespie) April 1, 2020, 12:22am 9

RH-57098 is fixed in the latest WIP

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Ray Intersection - Getting the hit geometry

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