Hi Martin, or actually in your case here it's not too difficult to repair the messed up offset because the messed up parts can be just deleted and copied from one of the good parts. Also because your pieces are all meeting up smoothly it should be possible to offset the surfaces individually and have their offsets match up with each other.

That's how I build the attached shelled version, I did an offset of just these separated individual surfaces (that is a more simple operation than offsets of joined surfaces which then have a lot of boundary processing to be done) with Distance = 0.5mm and Flip on:



Then I used Transform > Array > Circular to make the other faces from those, joined them all together (needed to scale down by 1/10 in size first before all would join), then trimmed off the bottom piece with a line to make it coplanar to the original part, built a planar surface between the 2 rings and then joined the outside part with the inner part to make the attached shelled result.

So anyway these types of steps can get you a final shelled result when the regular shell operation fails which is not particularly unusual I'm afraid.

Hope that helps!

- Michael

Hi, Michael.

On this occasion I used ViaCAD to do the shell, but I did come back to MoI, ran through the tutorial you showed and succeeded at the first attempt. I was pretty pleased that it didn't take too long to do either.


Thanks for your help!

Martin.

Hi Michael.

I don't know if this is classed as a bug or not, but I'll mention it anyway:-)

The following seems to be the case if a face is selected for extrusion: - If I first extrude a cube from a rectangle and then draw a simple curve coming off a top corner to use with Set path within the Extrude tool, then I have found the solid doesn't update if I go on to change the shape of either the path curve or the rectangle. Selecting the edges of the same face for extrusion works as expected although it creates a separate solid.


Martin.

Hi Martin,

> The following seems to be the case if a face is selected for extrusion: - <...>

Yes, unfortunately that's just a limitation on how the history mechanism currently works.

The history function is only able to work when all the inputs that went into the operation are able to be found in the current model.

In your case here the face that you selected as the input into the extrusion isn't present after doing the auto-booleaned extrusion, it's eliminated during the boolean operation. If you check the "Keep separate" option before you click "Set path" you should then get a result that will be able to update as you were looking for but the pieces will all be separate instead of booleaned together.

In the future I want to overhaul the history mechanism to keep a kind of parallel separate database of all previous objects in it so that operations like you're trying to do will work with history. That will involve a major effort though.

- Michael

Hi Michael.

It's not a big deal for me, because by selecting the top edges of the first solid rather than just its top face, this allows for the second solid to be updated either by resizing the rectangle or reshaping the extrude path curve. It was only when I found that selecting a face acted differently that I wondered if something needed a tweak.

Cheers.

Martin.