There is a post on GDL_Center that is talking about tube twisting and apparently there is a new macro in 21 called 'Gravity_tube' that may help.
http://gdl.graphisoft.com/forums/topic/tube-twisting
My only other suggestion is the TUBEA command that has no twist angle settings.
I have never used it so don't know what it would be like.
I have no idea about the shear angles.
Barry.
One of the forum moderators.
Versions 6.5 to 27
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