Hi Maxim, this seems to be a change in behavior in Keyshot?

It looks like they no longer read the actual NURBS data stored in the 3DM file and will only process polygon mesh data from the 3DM file. Rhino stores polygon mesh data attached to NURBS data when it does a shaded view, because Rhino's mesher is very slow so it tries to avoid recalculating it when it loads the file later on.

MoI has a fast display mesher, so MoI does not attempt to store the display meshes as additional data into the file since it increases file size by quite a bit.

You may want to contact Keyshot's support and ask why they have made this change and why they aren't able to process the NURBS data directly anymore.

At any rate, you can solve the problem by using OBJ format to export from MoI into KeyShot, rather than 3DM format. 3DM format will not work with MoI-generated 3DM files if they only try to access display mesh data alone, since MoI only stores NURBS data in 3DM files and doesn't try to store polygon mesh data in there as well.


> or even better, is there a fix planned for the 3dm file
> output to make geometry visible to Keyshot.

Well, no fix is really necessary since you can use OBJ format to transfer polygon mesh data from MoI into Keyshot. This will also allow you to adjust the density of the display mesh at export time from MoI.

It would not work very well for MoI to try and store display mesh data in the 3DM file as Rhino does, because MoI's display meshes are created with a different process than export meshes and are meant for the realtime shaded view and not for a full quality render. That's different than Rhino, since Rhino uses the same mesh mechanism for both export and for display meshes.

Since MoI has a different meshing process for realtime display versus export, it would not really be a great idea to store the realtime display mesh in the 3DM file such that it would be used by a rendering program for a full render, the export mesh as generated by OBJ export is more carefully constructed than the realtime display mesh and it's better to use the export mesh for a full render.

- Michael