Why did my component footprint pads change when placed?

[eric_engineer]

This seems really dangerous.  I have a footprint (From snapeda).  This is how it looks in my library:

Here it is in the library.

Here it is placed:

Clearly the hole and pad size has changed. I mean, you can't just do this. Do I have to now manually check every single footprint I use in case the tool just decides to change it? 

I assume this is going to relate to some DRC setting somehow but this is not cool.

---Edit---

I'm trying to have an open mind using this tool, but it is not easy. The way annular rings are calculated and then changed is pure madness. One might think the answer would be to specify a small enough annular ring in the DRC settings but no, you also have to account for the vague percent column which is not explained in the DRC menu. But if you search long enough you can find in a ten year old eagle thread https://eagle.suggest.eng.narkive.com/2nfikC83/prevent-restring-on-pads-that-are-not-defined-with-an...

It's encouraging that people have been asking for 10+ years for this to be done better.

[jorge_garcia · Accepted solution]

Hi @eric_engineer,

You can find the full explanation for how this works here:
https://www.autodesk.com/products/fusion-360/blog/what-you-didnt-know-about-eagle-restring/

If you are aware of what's going on it's pretty easy to workaround. Basically you just adjust the annular ring settings enough so that your settings in the library win over the DRC calculation. 

I agree it can be better and there is work in that direction. In the meantime you can reign it in using the information in the above blog post.

Remember that in this scenario the part would be flagged by the DRC as being in violation so you would find out about it before you go to manufacture the board. Additionally, this doesn't affect all parts and all designs. Generally you'll run into this on parts with thin annular rings.

Let me know if there's anything else I can do for you.

Best Regards,