Blocks - FBX scaling issues

Rhino Rhino for Windows
1

We have a Python script that exports linked blocks to FBX files, and one that re-assembles them as instances in Maya (using the xform matrix associated with each block in Rhino). We have come up with an issue where we have a file containing several linked blocks such that:

  1. some blocks the xform matrix contains a scaling of 39.37 and some a scale of 1.0 (identity)
  2. the main file and all the linked files all have model units set to inches.
  3. the measurements of the objects in each of the referenced files is consistent with those on the main file, after scaling (i.e. an brep that is 200 in in its own file, is 200 in in the main file even though the the block xform as 39.37 scale).
    NOTE: we tested one of the scaled objects by inserting it with the “Insertion point” checked and with it unchecked, with the following results:
  4. checked: the object is consistent with rest - xform scale 39.37
  5. unchecked: the object is 0.0254 in size (i.e. inches to meters) - xform scale identity

So, whereas in Rhino all instances look right in size, when recombining the FBX in Maya some instances are larger (the ones with 39.37 scale) then the others. Is there some information we are missing?

3

Hi ,

Can you try and copy-paste the geometry in a new file and use that to create the block? Might it be that the linked file contains a block that is scaled?

Best would be to post/upload the file(s) expressing this behavior here. It’s much more likely for someone to find the cause with the file at hand.

-Willem

4

Thanks Willem,

I have tested numerous arrangements without any conclusive results. In any case, our script is meant to work with files as they are delivered to the user - in fact, there is a good chance that some of these blocks were built from imported STEP or IGES files.

This issue occurs with two specific files, each containing blocks only, and possibly originated from non-Rhino sources. Unfortunately these files are NASA’s and contain confidential information.

I was hoping to find out if there is other information, aside from the ModelUnitSystem, that can be retrieved from the files so as to compensate for the discrepancy indicated in my previous post.

Thanks again for replying,
Marco