Thank you Michael! I swear I had tried screen distance but the first time I did it changed the first point I had selected when I was selecting the second. I was probably doing something wrong. Now it had worked properly.
I have found the same problem again. Trying to use screen distance with one part that is a imported step with a lot of surfaces, when I select the second point, the program changes the first point. So the problem may be with this part. ¿Maybe different units? Has anyone have this problem?
A couple of options to try: