Creating mold from solid

[wides]

I'm trying to remove 1.5mm from the outside surfaces of a solid model, to create a plaster mold.
The shape is of a duct, and has convolutions and a sweeping curve, that are resulting in errors when i try to offset all surfaces by 1.5mm.
Can i anyone offer a method to do this?
Note: i only have the basic license.

 

[jackk]

I would try THICKNESS (-1.5mm) to offset the sides of your solid. But depending on your solid, you might get the same types of offset errors.

Did you make the solid with the Multi-Section Solid tool?

You'll probably have to edit your model to get a clean transition of your duct shape.

 

[wides]

I tried the thickness function, and got denegarative surface error messages.

The existing part was scanned using a scanner, and then the solid was created in Rhino (i didnt scan it or use Rhino, this is how i received it, as a solid "lump")

Because of the shape of the duct, it isnt perfectly circular through the profile, so im trying to use existing geometry where possible.

I tried using multi section solid, but the profle changes from circular to oblong along the duct. I couldnt identify the same/similar profile through the section, so the profile would appear twisted when the section shape changed.
Thanks

 

[jackk]

To make your mold with CATIA, your only option is to clean up your solid geometry.

Take some section cuts of the Rhino data for reference, and create new, smooth sections to better define the multi-section solid.

Maybe you can go back to the scanner, and get scans at the specific section planes?

Maybe Rhino can offset the scanned surfaces?

 

[solid7]

That's not enirely true, jackk.

This will take some investigative analysis of the model, as you have said - but degenerative geometry is not just inverted normals, or tangency/curvature continuity issues.

wides - make absolute certain that you aren't trying to offset radii or curvature past their geometrical limits. If you have a 1mm radius, for example, you cannot make a 1mm offset. It's entirely possible that you may have to isolate your problem areas, and develop the mold to overcome these limitations.

You've got your work cut you for you on this project, running only a basic license, in any case. jackk was correct - you may want to go back to Rhino, first.

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