Raytraced materials April 2017


(Nathan 'jesterKing' Letwory) #1

Currently materials should all pretty much work. For the Raytraced mode we made one decision: no support for glossiness in Rhino Custom material.

Backfacing materials are also supported in Raytraced:

There are a few minor issues open on materials, but otherwise this part is considered done. Feel free to test and report bugs :slight_smile:

To see what the current open issues are you can look here at my issue list



Hi @nathanletwory,

I cannot see any changes when i adjust IOR value. Is there missing something ?

When switching from a red colored metal material to custom material, the color is now black and the reflection is red, adjusting the color does not anything. Is this expected ?



Is there a way to control the backfacing color via any material ?



Hi @nathanletwory, there seems to be a bug when using custom material as ground plane material together with the sun light. To reproduce:

Enable Sun lightning, assign a textured custom material to the groundplane, this is what i get (sorry for the funky texture):

Now after switching back the groundplane material to “shadow only” i still get the texture shown in all shadowed areas:


(Nathan 'jesterKing' Letwory) #5

There is only limited control as in you can either pick a color, or have it use the object color, or create a custom material (limited functionality):

(remember, no gloss)

Is this not what you are seeing?

Metal and Glass (and Gem) materials have the diffuse color set to black. For metals that are converted to Custom you should change the reflection material. For Glass/Gem materials that have been converted to Custom you should change the transparency color.

Changing the diffuse color in a custom material while Reflection (or Transparency) are set to 100% won’t show any visible changes. This is expected. Turn down the reflection or transparency amount to see the changed base color.

That is a bug indeed. Reported as RH-38730



Not in the custom material. Does IOR only apply when using transparency and reflection ? I was using itwith reflection only.


(Nathan 'jesterKing' Letwory) #7

IOR is for transparency, it is the Index Of Refraction:

Here a short video, not sped up (so can be a bit slow, I recorded it while using Rhino over VNC :° ):


What’s the reasoning behind this decision?


Hi @nathanletwory, i know what IOR is. If you right click the IOR field and if IOR does only apply for transparency, why does the IOR list include metals and multiple non transparent material IOR values at all ? This might confuse users. In this case i would consider disabling the IOR input field unless transparency is not zero.


(Willem Derks) #10

That would be a logical GUI setup indeed.

(Nathan 'jesterKing' Letwory) #11

Gloss as Rhino Render does it is incompatible with how Cycles works. Attempts to simulate theRhino render way result in ugly, and that we don’t want.

(Nathan 'jesterKing' Letwory) #12


(Andrew le Bihan) #13



The IOR for beer is 1.345, this does not apply to Guinness :beers:


(Brian Gillespie) #16

RH-38730 is fixed in the latest WIP


Here is a simple material test, it works good, but I have to switch to shaded to adjust layer material colors as the color adjustment pop-up doesn’t pop up while raytraced is running. (or at least it takes toooo long for me to wait, so I hit ESC
(as I can’t see the color dialog) and then close the material dialog and then switch to shaded and does the material adjustments and then switch to rendered again. Quite tedious as you understand)

It’s a simple file that is ran on the laptop. I made all the parts so you can have it if you like.
(the gems are just fakes so they are not based on proper cuts)

(it runs 3x faster on the i7 cpu than on the geforce 750m cuda gpu)

BTW: The render is OK, but as you can see lacking dispersion gives it a clear CGI look.