Precisely control location of cut in assembly

[larsrd]

I want to cut away something of a part in an assembly. So, I select a face of the part, Start 2D Sketch, and draw a rectangle, which I want to use as the shape to cut into my part. I want to control the position of this rectangle precisely. So, I select the Dimension tool and first click on one side of my rectangle. Then I try to click on an edge of a neighboring part in my assemply, because the cut rectangle needs to be a certain distance from this edge. However, I cannot make this edge - or any other edges in my assembly - active/light up/be selectable, instead the Dimension tool always gives me the length of the side of the rectangle I selected. I can extrude said rectangle and cut away from the part, but how can I control the precise location of this cut?

[elsiedav.is311804762]

Hey dude, Make sure that the nearby part you want to cut is not hidden or locked from view. If you're having trouble selecting it, try using the "Select Other" or "Select Tangency" options. Another option is to create a reference line or plane that you can use as a guide for where to make the cut. Once you've got that set up, you can use the Dimension tool to mark the exact spot where you want to make the cut, and then use the Extrude tool to cut the rectangle into the part.

[Bunny]

Can you project the edge of the neighboring part onto your sketch?

[henrik.ubbe]

If you just project the edge into your part, the other part becomes adaptive. Be careful when making parts adaptive to other parts in an assembly. This slows down IV a lot.

What I tend to do, If I am late in the design process and knows that things are unlikely to change is to make a sketch on the part and "Project cut edges". Be adviced that this is not updated if you later on need to move the part with the cut or the parts projected. It's dead data.
A more stable procedure would be to make a skeleton part wich contains as much information as you need, which you then can derive into both parts used.
Look into "skeletal modelling" for more info about this.