Hi list,
I am trying out ShootRay() on some very simple geometry. It seems that the rays intersect the untrimmed srf, which is not what I expect.
The green points are the ray origin, red dots and connecting lines are what ShootRay() gives me as the intersection points:
If I untrim the triangular srf, it becomes obvious that the ray shooter hits trimmed-off parts of the srf:
Bug?
This is on version 5SR12
Oh, and here are the model and script…
shoot_rays.3dm (62.8 KB)
shoot.py (314 Bytes)
Have a good weekend
Hi @axa,
unfortunately that is how it has always been and applies to vbscript, python and rhino common. The helpfile mentions:
Only Surface and Brep objects are currently supported. Trims are ignored on Breps.
Your script looks like you’re only interested in the first reflection point ? Why not intersect with a line or project the points and try to keep the closest one ? Below is an example script using projection and scene based on yours. Note that a projection can hit an object multiple times and goes in two directions…
ShootOneRayCustom.py (1.8 KB)
shoot_rays.3dm (90.7 KB)
c.
Hi Clement,
thank for pointing out the limitations of ShootRay(). I tend to work almost exclusively with the rs doclumentation
http://developer.rhino3d.com/api/RhinoScriptSyntax/win/
and was therefore blissfully unaware of this. With the limitations in place (no trimmed Breps, no meshes), ShootRays() is essentially useless for most tasks.
Thank you also for providing a ProjectPointsToBreps() example. Yes, for my particular application, this works very well. I’ve now re-written my code around rs.ProjectPointToSurface().
Have a good week
Any hope for this in Rhino 7 (ShootRay to work with Trimmed Breps and Mesh objects) ??
Couldn’t agree more.
–jarek
Hi @Jarek,
at least for meshes you could now use Rhino.Geometry.Intersect.Intersection.MeshRay. I’ve used it for breps (their rendermesh) as well and then pulled the points to the brep if required. But i agree, a method to work around this would be great.
_
c.
This is still on the to-do list.
https://mcneel.myjetbrains.com/youtrack/issue/RH-13351
The best you can do for now is shoot a ray at a surface and then see if the first intersection point falls on face’s active region using BrepFace.IsPointOnFace.
– Dale
It seems BrepFace.IsPointOnFace takes in a u,v parameter, so how can the point3d that is returned by shootray be turned into a u,v? Would this also mean you need to iterate through every brep object and every face of those objects that were passed to shootray as an IEnumerable?
Use BrepFace.ClosestPoint.
– Dale
Is there a way to just make a new brep that does not include the trimmed part?
unless I am missing something, if I have 1000 brep objects and do shootray, I can pass those 1000 breps, but then need to make a for loop to go over each one and use ClosestPoint, correct?
thank you
Hi @umcadop,
Generally speaking, no.
What are you trying to do, or what problem are you trying to solve? Perhaps Intersection.RayShoot isn’t the best tool for your task?
– Dale
Not exactly that, but you could mesh your Brep and use the MeshRay intersection method instead. That doesn’t do reflections though, but you could script that as well.
