Need to understand 3d model units and systems

[JamesMaeding]

I have the need to bring in 3d faces from acad at correct coords.

The 3d faces are from an exploded civil 3d surface. My question really applies to both 3d faces and 3d solids from acad though.

To investigate, I did a simple test.

I made a 100' square surface at elevation 0 using C3D, and explorted as IMX.

I also made 4 3d boxes which were 10'x10'x10', and each was 100' apart.

I tried a few methods of making fbx and 3ds files to bring into AIM.

One was adding boxes to navisworks and exporting to fbx.

The other was importing boxes into 3ds max and exporting as 3ds and fbx.

The same thing happened with all of them when I bring into AIM on real coords, CA83-VIF in my case.

They all come in at the correct elevation (0.0), but they come in rotated about 15 degrees, and their 0,0 does not line up with the surface's 0,0, see image below. Note that the bottom faces of the lower boxes are on the same plane with the grey flat surface.

So I am trying to understand why there would be a rotation involved, given that both th surface and boxes came from the same acad drawing, and were lined up in the drawing.

The coord system I am using should not matter, any transformations should have been done to both, as they were brought in.

I have all kinds of other things like bridges and pipelines that exist as 3d solids in acad, that I need to bring in to correct coords, so understanding the units and coord systems of fbx and 3ds is key to that.

thanks

[JamesMaeding]

No replies?

This is an emerging product and no Autodesk employee is interested?

Guess they are forced to answer since I am on sub. Lame though.