Extrusion layer with CS5.3.1

[YohannEude]

Here a configuration which doesn't work with CS 5.3.1. There are two images attached to this mail:

• On the first image, the red face has no extrusion layer (All is Ok)
• On the second image, the red face has an extrusion layer (CS adds a strange step )

Thanks for your work,

Yohann

[YvanFournier]

Without the setup data, I cannot ensure this is not a bug, but is seems to be normal behavior for the current algorithm.

The "step" would be desired if the red area were for example the wall of a pie and the grey area the inlets/outlet. Zones outside the red (extruded) area should automatically be sliding sections (to avoid issue #8), which might also help here

To avoid this step, blocking the boundary layer in the gray zone parallel to the red zone (using a boundary layer insertion with zero thicknes) should work around this.

For better automation, some test based on vertex normals at insertion / no insertion boundaries (i.e. setting zero thickness when the vertex normal is too closely aligned with the non-extruded zone) might be feasible.

[YohannEude]

Your are right, the grey area near the red one is an inlet/outlet. I don't want to put the thickness to 0 on the red one because I have some pipe with an extrusion layer sliding on the inlet/outlet.
For this case, maybe I would add first the extrusion layer around the pipes and then fix the thickness of the grey area (inlet/outlet) to 0 and add the extrusion layer on the red part.

[YohannEude]

In two steps, it works! Thx

[YvanFournier]

Ok, automating this is tricky (it is easy to determine cases when the surfaces are on the same plane, as they are here, or orthogonal, such as in a duct inlet, but could be fragile for some geometries).

The chosen solution would be to add documentation on this feature explaining the usage an pitfalls, with a few screenshots similar to yours (possibly in a simpler, 2d illustration).

So I am not closing the issue yet, but moving it to "documentation" category. I'll close it when the documentation is up to the required level.