I’m currently moving a scene from Rhino to Blender for a 3-second exploded view animation. I’m using the import_3dm plugin for the transfer.
I’ve noticed a significant visual difference that I can’t explain. I’m using the exact same HDRI and the exact same Cycles engine in both apps, but the results are worlds apart:
Rhino Render: Looks vibrant, punchy, and the polycarbonate cover is bright and clear.
Blender Render: Looks much duller, and the internal parts of the model appear darker.
I’m curious about the technical reason behind this. Does Rhino apply a specific default Tone Mapping or Gamma correction that Blender doesn’t? Or is the Light Path handling for transparent objects different by default in Rhino’s implementation of Cycles?
I’m also wondering if the way Rhino tessellates the mesh (creating many triangles) affects how Cycles calculates light compared to a cleaner mesh, or if it’s purely a color management difference.
It is probably due to how materials are imported. Could you attach a 3dm file with the object and material you are trying to import?
Please also add screenshots of the Rhino Render results and screenshots of the material settings for all materials in question. I no longer have a Rhino copy, so I need the visual aids to guide me through figuring out what the issue could be.
Hi, thank you. I’ve uploaded files and my Rhino render settings to Google Drive. I also recorded a video showing the steps I took after importing the file into Blender.
As you can see at the end of the video, even though all settings are the same, the plexiglass looks much more vivid in Rhino. Also, Blender makes the object behind the plexiglass appear much darker and duller, whereas in Rhino, it looks exactly as I want it to.
I think I’ve finally managed to get very close to the Rhino look!
The biggest breakthrough was finding the ‘Shadow’ toggle under the Ray Visibility settings for the transparent material; turning that off significantly improved the light pass-through and overall clarity.
However, I found that relying solely on HDRI wasn’t enough to match Rhino’s quality. I had to add 3 rectangular (Area) lights and dial the HDRI strength down to 0.10 to balance the scene. It was quite a challenge to reach this point, and while the exploded view still feels a bit different than Rhino’s native output, I’m satisfied with the result.
Here is the side-by-side comparison: Rhino (Left) vs. Blender (Right).
Looks like your cycles image needs more samples or more time to render. I see more detail in the blender version but it looks only partially developed/rendered. The rhino version looks better on the metal parts, looks like some mesh artifacts in the blender version on the metal.
Have you tried rendering your project using Eevee? I think it might work well and be much faster and less error prone for animation than using cycles. You may run into some denoising issues with cycles and animation though current Blender versions seem better at that. Sorry don’t have any advice on the materials.
The current import_3dm version does not do a one-for-one import of materials, but was a first-effort to get some stuff in.
Materials in Rhino are quite complex actually.
If a material is PBR based (basically everything except Custom, Picture and Plaster) see the codeblock starting here:
The rest is starting at:
If you don’t mind I have one more request for some files:
Tools > Options > Advanced
Type in ‘dump’ in the settings search box
Set the setting for dumping material graphs to true (DumpMaterialShaderGraph)
Switch a view to Raytraced or run _Render
Find on your home directory (%USERPROFILE%) a bunch of .dot files
Zip them and attach them to a reply in this thread
Remember to set the advanced setting back to false
The files generated are DOT files that graphviz (graphviz.org) can transform into visual graphs. That way you can see how a material shader looks like in Rhino Cycles.
It would help a lot in figuring out a way to improve the material import into Blender.
I think I’ve found the culprit! In the Object Properties panel, under Visibility, I unchecked the ‘Shadow’ option. This immediately brought the look much closer to the Rhino Cycles output. It seems like the object’s own shadow was causing the darkening/blackness in Blender.
Also, to keep things consistent, I’ve matched my Blender Cycles settings to my Rhino defaults:
Max Samples: 1000
Seed: 128 (set under Sampling > Advanced)
I’m curious if there are any other specific methodology differences between how Rhino and Blender calculate these samples that might affect the ‘vividness’ of the final render. I’ve updated the Google Drive link with my latest Blender settings, material nodes, and the improved renders for you to compare.
Blender is truly an incredibly deep software with so many hidden layers of control! I hope these help with improving the import_3dm material conversion.
