Rhino 7: Materials assigned to layers randomly changing

I have a Rhino 7 file with materials assigned to layers in order to quickly assign materials in Twinmotion. However, often when I re-open the file, the layer materials will have changed. I am the only person working on this file, and the materials are ones which I would never assign (for example, assigning softscape to millwork hardware). Has anyone else experienced this issue?


Hi Chris - are these Rhino materials? Are there blocks involved?


Hi Pascal,

They are Rhino materials. Basically just a renamed default plaster material, so that I can quickly replace the material in Twinmotion. No blocks involved.



Hi Chris - can you please send an example file (the smaller the better, as long as it shows the problem) to tech@mcneel.com, with a link back to this topic in your comments?


Hi Pascal,

Hopefully this file shows the issue. I find it is when I reopen the file that the layer materials will have changed. I have included the layers above, which seem to be the most likely to change.

Layer change example file.3dm (2.8 MB)

Hi Chris - as the file opens, the materials look like this:

Is that what you expect? Is that not what you see? What should I do to make it do the bad thing?
Are you saving the file locally, or on a network, or a GoogleDrive.DropBox type thing?


I have the same issue. Rhino 7 SR28. Working on a 200mb file, lots of layers and materials. All of the materials are standard Rhino materials. Everything saved locally.

The problem happens frequently but I don’t know what triggers it so I can’t suggest how to manually reproduce it.

FWIW I’ve noticed Detail-specific layer properties randomly resetting as well. Things like line weight and print color.

Bumping this issue too - this week on 7SR31. The whenever I changed to a different layer state, the materials were scrambled on random objects.

Had to delete all materials from file then re-import and apply them all. They were just basic flat colour materials as well.

Just bumping this up as I’m having the same problem. I’ll set up all of my layers with materials and then they get switched up. It seems to be related to the Layer State manager. If I change a layer’s materials and then go to the Layer State manager and click one one of the states, the layer reverts to the previous (or maybe even a random) material. I’m using Rhino Version 7 SR32.

After a bit more testing, it looks like the Layer State manager saves the state of a layer in the past, not how it has been updated with a new material. For example,

  • I have Layer_1 with Material_A assigned to it and make a Layer State named State_One.
  • I change the material on Layer_1 to be Material B and save a new state called State_Two.
  • If I click between State_One and State_Two, the material on Layer_1 changes.

This seems like a bug to me. Shouldn’t the layer state simply save the visibility of a layer, not the materials that were assigned to it at one point in the past?

I see now that at the bottom of the layer state manager there are the settings to restore and one of them is material. That’s impressive that you can restore all of those things, but it seems like that those should not be set as the defaults. I guess I can imagine a scenario where you might want to change everything about a layer, but 99% it seems like visibility would be the only thing you would want to change. So I guess this is a feature request verging on a bug.

Hello- you get to choose what layer states are restored, in the Layer States panel
Does that explain what you are seeing?


Yes, I understand this now. In typical fashion, Rhino gives more options than 99.99% of users would need. Impressive, but also too much at times. My request is that the defaults on the settings get changed so only layer visibility is saved and then users can add other things if that is necessary.

In addition, some of the layers that I noticed the material changing were never assigned materials that appeared when I used the layer state. I think there are two separate issues here: a) the interface is confusing for users and the defaults should be changed to simplify user experience, and b) there seems to be a bug in the layer state manager as the materials are being swapped to layers that never had those materials at any point.

1 Like