intersection of three-dimensional objects at a point or along a line

sergei_nesterov

often, performing sketches or carried out by Boolean operations, the parts are in contact with each other at the single point or line. This leads to an error in the construction of the figure. I have to do additional microscopic gaps. These are additional labor costs. I understand that the problem is mathematical in nature. The problem is frequent, tired of encountering it, I decided to ask a question. What do the creators recommend? Are they trying to solve the problem? What are regular users doing? 

NeilCooke

You are right, it is mathematical. Solid volumes need exactly that - a volume - and there is no volume at an infinitely small intersection. If you were to make this in real life (3D printing does not count), how would you make it?

sergei_nesterov

I guess I incorrectly expressed my thought. I agree that for individual parts it is impossible to carry out Boolean operations if they intersect only at one point or along a line. But this is possible when touching on a plane. In my drawing there are two cylinders and one common base (plate). I can attach each cylinder to the base if they are at a distance from each other. Why can't I do this when the cylinders touch tangentially?

NeilCooke

For the exact same reason above. If they are separate parts attached to a plate then they should be modeled as separate parts and assembled. Any boolean operation includes all selected geometry and hence the error.