Extrude with a parameter that is currently zero

[daviddoria]

Say I have two user parameters that are not necessarily, but could be, the same, 'A' and 'B'. Now say I want to use the value 'A-B' for a value in a Feature, like the Distance of an Extrude. If A currently equals B, and I try 'A-B' as the Distance, the OK button is greyed out for the Extrude, presumably because "there is nothing to do". But "nothing" is exactly what I want it to do right now with these parameter values, but if I change them later, I would want the Extrude to change accordingly.

How is this usually handled?

Thanks!

David

[davebYYPCU]

Make the extrude with uneven values, then observe what happens with the required parameters after that.

Might help….

[daviddoria]

I did try that actually, but I didn't understand the error though when I set A==B:

Warning: Extrude2
<b>1 Reference Failures</b><br/>Cannot extend extrusion to object. The extrusion profile falls outside the boundary of the selected body. Select a face or plane instead, or adjust the profile so that it falls inside the boundary of the selected body.

[davebYYPCU]

That error message is telling you that you are also Extruding to an Object, where the desired behavior has to fail.

Works here, change first extrude to equal second extrude distance.

[daviddoria]

In your example both sketches are from the same plane, I don't know if that matters? Here's my order of operations:

- Create two User Parameters - P1=1mm and P2=2mm

- Create Sketch 1 on the XY plane

- Extrude Sketch 1 into Extrude1 (arbitrary distance, in this example I used 20mm)

- Create Sketch 2 on the top surface of Extrude1

- Extrude Sketch 2 into Extrude2 to a distance of P2-P1 (which currently equals 1mm)

- At this point everything is as expected

- Change P2 to 1mm (so that P2-P1 now equals 0mm)

- At this point I get the error, where I would have expected simple to be left with geometry that is exactly the same as only Extrude1 (as if Extrude 2 never happened).

See what I mean? I've attached files in the two states explained above.

Thanks!

[daviddoria]

Any further thoughts?

[g-andresen]

Hi,

In future, please reply to a single post and not by post reply to the thread opener, as in this case to yourself.

This has the effect that we know what the answer refers to.

günther