V6 Bug: Raytraced Mode Ignores Clipping Plane

Brenda · May 7, 2019, 1:01am

On nVidia, fairly recent drivers, the Cycles/Raytraced mode ignores the clipping plane.

nathanletwory · May 7, 2019, 3:37am

Clipping Planes will come in v7

Brenda · May 8, 2019, 3:28am

Sigh.

Michael_Pryor · May 8, 2019, 3:32am

In the meantime you could split the geometry and hide half of it (not ideal, but it works)

Brenda · May 8, 2019, 4:04am

As long as we know, deep down, that it’s a bug.

nathanletwory · May 8, 2019, 4:07am

During the v6 WIP there was for a while support for clipping planes - or actually even clipping volumes (add a box or sphere, mark it as clipping volume and then switch to Raytraced). The problem was that on the GPU it would more often than not freeze the entire machine, so I decided to pull it until the day I got that properly fixed. Alas, that day is still in our collective futures.

Here an old video of when I worked on it:

(I thought I had uploaded more, and nicer, videos of my clipping plane work to youtube, but apparently I uploaded only this one, I’ll see if I can dig up some of the other videos and screenshots I did).

Brenda · May 8, 2019, 4:23am

That’s pretty advanced. It’s almost like a frustrum chop, but then you have to add those pesky surfaces.

For V7, it would be cool to be able to add a custom material for the chopped surfaces, such as a hatch texture, or the a single color.

nathanletwory · May 8, 2019, 5:53am

That should be quite possible indeed. The current plan is that I get back to v7/Raytraced properly during the summer (Mac porting tasks keep propping up on my todolist). That is including clipping planes.

I don’t have to work from scratch then though, this code lies dormant:

github.com

mcneel/RhinoCycles/blob/0996cdf6fefb0142858b30e67d81813322dbb0be/Database/ChangeDatabase.cs#L480


					ClippingPlanes[cp.Id] = new Plane(cp.Plane);
				else
					ClippingPlanes.Remove(cp.Id);
			}
			sceneBoundingBoxDirty = true;
			CalculateClippingObjects();
		}


		public void CalculateClippingObjects()
		{
			if (SupportClippingPlanes && sceneBoundingBoxDirty)
			{
#if DOCAMCLIP
				var camplane = Plane.WorldXY;
				camplane.Transform(CurrentTransform?.ToRhinoTransform() ?? Rhino.Geometry.Transform.Identity);
				Interval interval = new Interval(-0.1, 0.1);
				Interval biginterval = new Interval(-50, 50);
				var camera = new Box(camplane, interval, interval, interval);
				var cammesh = Rhino.Geometry.Mesh.CreateFromBox(camera, 1, 1, 1);
#endif

robinp · May 24, 2019, 11:18am

yeah, this would be great. I’ve been wanting a custom surface / material for cut surfaces for ages. Your example is very good. Would be wonderful for architecture as well as product design.