Using an additive loft to cut a hole

[Mjointy]

Hi all, first post so please don't destroy the noob...

I've only been using freecad for 3 days and spent most of that reading in here, and watching youtube, but cant find what i "want" to do, because it may not be possible.
I did use a manual workaround, but my edges were not meeting exactly... so I'll explain what i'm trying to do...

1. created two sketches
2. made an additive loft from one to the other
3. used thickness on the loft to create 5mm walls and bottom but open top.
4. created a 2nd body
5. created a pad wider than the additive loft X & Y
6. centered the pad around the loft
This is where I'm stuck:

7. join them together with the pad around the "thickness", so the loft scoops out its shape from the pad.
Basically imagine a rectangular top hat with a brim round its middle.

I've tried joining the thickness to the pad, the pad to the loft, making things solid.
Problem is i really dont know what should be joined to what (is a loft a solid or a "thickness" an object etc? sorry to be so thick!

Now to see how to attach my file

Many thanks
Martin

tophattest.FCStd

freecad test project

(121.78 KiB) Downloaded 3 times

[chrisb]

1) Hi and welcome to the forum!

2) It doesn't work, because thickness is very picky and thus the first body shows errors if checked with Part->CheckGeometry, BOPChecks included.

3) If it wasn't for point 2) you could have used (but shouldn't, see below) a Boolean cut in Part workbench. However, this would have left you with two slices of the loft, and not the hat you describe. You would have needed an additional inner rectangle to get the hat.

4) You should not mix Part and PartDesign, if it isn't really necessary until you know what you are doing.

5) What can you do: In this case you should probably have used a pocket inside of Body for the collar. Avoid thickness and use an inner subtractive loft.

[Mjointy]

Thanks, i'll read up on all that.

M