Wrong scale of the Zephyr model when importing into 3ds Max

[hamoni]

Hi everyone!

I am having an issue when exporting a Zephyr 3D model as a .FBX and importing it into 3ds max:

In Zephyr, the scale is correct, the car is about 4.8m long, which is correct. Now, when I import that model into 3ds max, that car length is about 0.353m. Rescaling it by a round number (x10, x100 etc) doesn't give me the right scale, obviously. I tried rescaling it by x2.54 (inches) but still no luck. In 3ds max, my system units are set to be 1 unit=1cm.

Does anyone know how to get in Max the exact same scale as it's in Zephyr please (real-world scale)?

a NOTE please: When exporting the scan from Zephyr and when I don't turn on "local rendering system" than the scale gets correct. but since it's so far away from 0,0,0 axis in 3ds max, the whole model looks really blocky, like Minecraft, it's unusable. When I turn on "local rendering system" while exporting it from Zephyr, then the scale gets messed up but the model looks fine, since it's close to the 0,0,0 axis.


Thank you very much

[cam3d]

Hi hamoni - Thanks for letting us know the issues you're facing. Here are my thoughts:

1. Generally speaking, most 3D files are *unitless* and there are plenty of compatibility issues between 3D programs (most commonly imperial vs. metric scale conversions).

2. I'm not familiar with 3DS Max, but you could make a 1x1 cube in that, import it into Zephyr, then see what the relative difference is between the two programs.

3. If the dataset is georeferenced (GPS) then Zephyr automatically saves the mesh vertices with double-precision (no rounding errors etc...) - LOTS of software doesn't support double precision data (as you have found out), so to import successfully it needs to be converted to a Local Rendering Reference System.

4. As Local Rendering Reference strips out this transformation data you lose the scale. You'd need to use control points to rescale prior to export.

https://www.3dflow.net/technology/documents/3df-zephyr-tutorials/tutorial-manage-control-points-distances-3df-zephyr/