Decal Projection changes despite same input

Questions
1

Hello I’m trying to allow a user to scale or rotate a decal after it has been placed. However I’m running into an issue where if I try to create a new decal with the same position and normal as the previous decal, I don’t get the same appearance, and this gets worse if the mesh that the decal is parented to is rotated from when the decal was originally placed. Any idea how I can fix this?

Playground example:Babylon.js Playground
Click to place a decal, hold right click to rotate the cat, middle mouse to scale the decal.
Observation: after placement, scaling the decal causes the new decal to have a different orientation. This can be further reproduced if the cat is rotated and then the decal is scaled again.

2

@Evgeni_Popov might have some ideas ?

3

Welcome aboard!

You should recompute the world matrix of the projector before generating the decal:

There are still some small shift of orientations sometimes when you rotate the cat, I think because the computations are not exactly the same as the vertices (as well as the projector position) have been transformed by the rotation of the cat.

4

Ah thanks, recomputing the world matrix does improve the issue.

Hm any ideas how to reproduce the same orientation if the cat is rotated?

5

No ideas for this one…