asset "Y_UP"

Hello, I’m having a problem to realize the correct matrix to transform an X_UP or Z_UP reference system to the Y_UP (our default) reference system. My main problem is that with a right handed system I am not able to build a complete reference system with only one input data (the vertical axis). I need at last two axis to complete the system. I know that there should be any convention that I am not aware of it, so I need a bit of help :slight_smile:

You do have 2 pieces of information.

  1. COLLADA coordinate system is right-handed, meaing it follows the right hand rule of thumb.
  2. COLLADA indicates which axis is up. By default it is the Y axis.

Therefore the default coordinate system is +X to the right (thumb), +Y upwards (1st finger), +Z inwards towards the viewer (2nd finger). Positive rotations are counter clockwise (again right handed).

I’ve done a search of the web to find a paper that I think will explain the conventions to you using column matrices (like COLLADA does).

3-D Transformations

I hope this helps you.