When using CAD software to draw board layouts, is there any convention on how to represent heatsinks attached to, say, some power transistors? I want to make sure they don't interfere with one another, and representing them on the board layout makes it easier to spot problems when I am moving stuff around.
It seems to me the alternatives are:
- represent heatsinks as a separate component
- modify the transistor's footprint so that it includes the heatsink
- just draw the heatsinks on some separate layer that's normally off, and turn it on when checking for interferences
So far, I am very partial to the first option, and have been making heatsink components on Eagle and adding them right next to the transistors:
However, I've never seen anyone do it like this. Is this a bad idea? Is there any sort of convention on that?