I've posted about this before, without including a relevant file, but the problem is getting worse and worse and I have no idea why. I create many different molds for skateboards, using incredibly organic-looking yet controlled curvatures, which depend heavily upon radial curves (arcs). My objective is to create framework sketches which use the least amount of dimensions, while imbuing the most adjustability, and Inventor supplies a ton of constraints to help with that. HOWEVER, when I try and use these referential constraints (such as: "equal" "colinear" "tangent" etc.) along with arcs it tends to screw the entire sketch up, giving me over-constraint error messages at nearly every turn (sometimes not even allowing me to connect a line between two points). This phenomenon has been occuring earlier and earlier in the creation of my part files, and in this most recent one it has happened in only the SECOND sketch. Over the last few months (when this started happening) I have found some workarounds and ways to deal with this problem, but recently those methods themselves have started to fail as well. I have auto-constraints and auto-dimensioning turned off, I like creating constraints as I go to control sketches in an absolute manner. I'm at wit's end, as this shouldn't be close to any semblance of the problem it is for me, sketches are supposed to be the least complex/problematic areas of a part when looked at individually.
The file I have attached titled "Completed Example" is a mold I created a few days ago with very few issues, but is tenfold more complex than the mold file titled "Failed" was intended to be.
![Autodesk Design & Make Report](https://forums.autodesk.com/t5/image/serverpage/image-id/1350519iCB55845EBFC43016/image-size/large?v=v2&px=999" "Autodesk Design & Make Report")