How to remove a part of object

[grzesiug]

Hi
i have drawn almost whole model from attached scetch, but i don't know how to corect remove a part of pipe between two walls.
Pleas give me some advise.

[chrisb]

You can add the cylinder in two pieces from the outside, each of them going to first face.

[Olav]

This thread encouraged me to try for myself.

You can add the cylinder in two pieces from the outside, each of them going to first face.

Not with a fillet in place, because then it goes from this:

Schermafdruk_2020-10-04_17-54-48.png (268.3 KiB) Viewed 454 times

To this:

Schermafdruk_2020-10-04_17-55-44.png (290.33 KiB) Viewed 454 times

(Resulting cylinder goes on for more than 9 metres in the Y-direction!)

You can't do the fillet after adding the cylinder either, because FreeCAD refuses to do it.

My provisional solution is to pad the cylinder to a fixed dimension (in this case 40mm conform the drawing). And then hollow the body out by making a boolean cut with a different (smaller) body I made for the purpose.

Menu_021.png (83.12 KiB) Viewed 454 times

Still can't make all the necessary fillets though. I understand that people are working on the fillet problem in FreeCAD, I fervently hope they will succeed in fixing it.

[grzesiug]

Thanks Olav, You are right.
I was thinking about boolean operation but I was hope that there is easier way.
Boolean cut solves problem.

[Olav]

Thanks Olav, You are right.
I was thinking about boolean operation but I was hope that there is easier way.
Boolean cut solves problem.

You're welcome. Let me know If you succeed in making the fillets!

[drmacro]

The trick is to keep you fillets from impinging on other edges or creating coplaner issues.

modelmania.png (172.11 KiB) Viewed 375 times

[Olav]

The trick is to keep you fillets from impinging on other edges or creating coplaner issues.

Yes, and that's of course a good solution/workaround if you have complete freedom to decide on your model. But if you need to conform to given dimensions and specifications it may not always be an acceptable option.

Even worse is the fact that it can be quite unpredictable. Sometimes compound/complex fillets will work just fine, then you change an unrelated thing in your design and FreeCAD will suddenly refuse making the fillets that previously were no problem for it at all. Or even crash.

Again, I'm aware that the developers are aware of this. So I'm not complaining and I'm waiting patiently but with great anticipation for it to be resolved.

[GlouGlou]

Freecad doesn't like this tricky fillet, but with some approximation...
link to download: https://mon-partage.fr/f/vmusgfLD/

[freedman]

I moved the outer radius sketch (of the pipe) down a ways and created the fillet, then moved the sketch slowly back up and got within a micron of having the two top edges aligned. Not bad.

[mrdic]

Years ago, ACIS used to have the same shortcoming, but a minutely small sphere centred at the degenerative convergence point subtracted from the part would permit the filleting and could be ignored in production. I remember doing this exercise, from the annual SolidWorks University that Dassault Systemes used to convene in the US, with TurboCAD V10, using that technique.