mest79:
The command to use is
PICTURE expression, a, b, mask, you can read about it in the GDL Reference Guide. It is used in the
Picture 19 object > 3D Script > Lines 179, 182 and 184.
You should add a Signature to your Profile (click the Profile button near the top of this page) with your ArchiCAD version and operating system (see mine for an example) for more accurate help in this forum.
David