Raytraced display mode is unmitigated disaster!

Rhino 6.30 (2020-10-14) cannot display SubD objects in the raytraced display mode. When I view the SubD objects in the raytraced display mode, the viewport is uniformly white, while the status bar shows progress in rendering. When I tumble the raytraced view, sometimes arctic display mode appears for a small fraction of a second.

Rhino 7 displays SubD objects in the raytraced mode as clouds of dots (shown in the following screenshot). The latest release of Rhino 7 (7.0.20301.12003, 2020-10-27) crashed when I viewed non-SubD object in the raytraced mode. Previous release of Rhino 7 crashed when I viewed SubD objects in the raytraced mode. The outline of the raytraced viewport sometimes trembles chaotically in Rhino 7.

No matter what I display in the raytraced mode of Rhino 6 or 7, Rhino temporarily freezes. It takes me at least one minute to escape from the raytraced display mode because Rhino temporarily freezes. Rhino 7 intermittently shows “Not Responding” message in its window title. (In my opinion, there should be a stop button in the raytraced display mode.)

The rendering panel has ‘reset to defaults’ button. This button does not improve the raytraced display mode in Rhino 6 or Rhino 7.

I use Quadro K2000M graphics card (NVIDIA driver 426.78, 2020-6-24). My laptop has 2GB of dedicated video RAM and 15.8GB of shared video RAM.

Looks like you have set raytraced to run just one pass:

Select the 1 after the slash and set it to 50 or whatever cycle count you are comfortable with.

You also appear to have inverted your view and I find doing that does seem to be a problem in Raytraced (? @nathanletwory) as here:

Raytraced.3dm (140.4 KB)


When you invert like that the ground plane is above your objects. Objects can not be visible through the ground plane with shadows-only set in Raytraced. The groundplane is still otherwise an object and occludes what is behind it, the background is the exception.

Thanks @nathanletwory. Given that Raytraced is set to use Render settings, could some consideration be given to the two modes behaving consistently, at least under that condition?

And shouldn’t the ground plane be infinite, thereby blocking all rays when seen from below? A black scene seems more appropriate than one which shows the light source as in my example.

[maybe this should be split off into a separate thread?]

And what about this, @nathanletwory ?

Perhaps we need to see your system info and your file @andrew.nowicki ?

I see no problems with Raytraced using either SubD or non-SubD objects. I have been modelling the past week a lot with these for Rhino Render PBR examples. Earlier today I created this non-subd model no problem, much of it while one viewport was running Raytraced. And all that on a MacOS, no less.

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The file/model was made by Robert McNeel & Associates to demonstrate SubDs in Rhino 6: SubDs.3dm (188.3 KB)

system info.txt (1.9 KB)

I set it to 10. You can see the result in the following screenshot. By the way, Render command is faster than the raytraced display mode and it makes much better (higher quality) images.

Does the raytraced display mode utilize shared video RAM? To the best of my knowledge, the raytraced display mode performs well on powerful GPUs which have lots of dedicated video RAM. My laptop computer is different - it has small amount of dedicated video RAM, and lots of shared video RAM. I can display 4k videos at 60 frames per second without glitches, but I cannot use the raytraced display mode. Apparently the problem is not that my computer is slow, but that the raytraced display mode is buggy.

Hello - a good default minimum number of samples for the raytraced viewport is maybe 50. The renderer uses 50 as ‘draft mode’.


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Just tried @andrew.nowicki’s file on my ageing Surface Book and it takes an age to raytrace (but that’s what I’d expect and I would only use raytraced on a laptop in an emergency). Rhino crashed when I tried to change the viewport from Raytraced to Rendered (I’d swapped modes a few times before without issue). Crash report submitted and cross-ref’d to this thread.

Rhino has traditionally been really stable on the Book, as but I’ve recently installed the Windows 2004 update and updated firmware, including the Nvidia driver, the context has changed. I’ll try to find time to try the file on my desktop which has the graphics oomph Andrew refers to.

It needs CUDA cores for this. Your K2000M is a few generations old and doesn’t have very many of them(it’s got a few hundred instead of modern cards that have thousands,) it’s not going to work great. Only having 2GB of video ram can also be a problem.

And another laptop crash, while rotating the view while in raytraced mode. Crash report submitted.

My laptop (ThinkPad W530) has 15.6 inch LCD with HD (HD=1920x1080) resolution. I have connected it to 4k monitor (Dell U2718Q). A moment ago I disconnected the 4k monitor and I ran the raytraced display mode on the laptop LCD. You can see the quality of display in the following screenshot:

In my desktop which has 64GB of memory, a P4000 driving the monitor and an RTX2080 for CUDA calcs, I can do the stuff that crashes my laptop without any problems.

I would add that using a laptop with relatively limited resources is an important use case for people on the road (often in high-pressure scenarios involving clients), studying, or working from home. I hope that such kit is a routine part of the McNeel testing environment.

Yeah your video card really isn’t adequate for trying to do raytracing on a 4k monitor.

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People have been whining for over 20 years, dating back to before video cards really did very much, that rhino doesn’t support the most advanced GPU features available. It was designed to run on a potato but couldnt take advantage of better hardware. Now as of V6 that changed, we’ve got this raytracing and more advanced OpenGL stuff that’s exponentially faster on decent hardware, and…we get complaints that potatoes can’t do high end GPU effects. It’s like, what did you expect?


My Thinkpad laptop has faster CPU and more RAM than most new laptops sold today. For me this is a matter of time rather than money - I have plenty of money, but I do not have time to configure new laptop. Besides, I like my old laptop because it has wide ultrabay. New Thinkpads do not have ultrabay, only small pockets for small devices. If I need lots of fast storage, I have to purchase three SSDs (solid state drives).

I’d like the potato to either do it very slow or fail gracefully, not crash. That’s a reasonable expectation.

But if it doesn’t, I can always put a cheap knock-off battery in it and get fried potato.

I’m with Jim on this… your video card is not powerful enough to run 2 monitors especially at 4k… Your rendering performance for v7 will not be awesome on this machine.

Sure maybe but we’re talking about GPU features–stuff where the whole sales pitch is that it doesn’t use the CPU–for which it’s 3 generations out of date. It doesn’t have enough CUDA cores or memory for this feature, it was a poor value “mid ranged” product when new, which was a long time ago.