How to trim a part using another part in Assembly
I would like to know how I can cut a part with another one in Assembly while connecting two profiles for weld. I tried Cut extrude, but as you see the result doesn't seem so good
I don't think it is possible to connect individual parts in an assembly, and weldment features are a part mode thing.
You could save the assembly as a part and then 'combine' the bodies to connect them, but you'll lose reference to the original part files.
A better way might be to do the work in a part file, you can use 'insert part' to bring outside parts into a new part and combine them together, subtract one from the other, build references between them, etc. and maintain reference to the original parts (changes to inserted parts will propagate to the new part).
I'm not sure which method would suit you better without know exactly what you're trying to accomplish.
You can edit one part in the context of the assembly. Once in this mode you could use the Indent command to cut one part with another. It works just like the Combine (or subtract) tool, but you'll have both parts remaining at the end.
Give it a try.
You could always cheat and edit the part in assembly mode.
Section cut the tube in half so you can see where you've working, open a new sketch on the face that needs cut, change transparency, convert entities from the intersecting tube, and cut.
It's not the correct way to go about it, and its not as quick as Fred's method, but would give likewise results.