Help! "Sketch Geometry is Overconstrained"! Won't add new constraints...

[tima123d]

I have a fairly complicated parametric sketch.

It is designed to make a complex plastic part.

I have it set up to be easily modified by a set of parameters.

 The parameters do not change the sketch as anticipated.

If I try to fix the constraints, it says "Sketch Geometry is Over-constrained":

But, somehow, I can move the individual points (although it is very slow to do so), so evidently it isn't really that constrained.

I have tried deleting ALL of the constraints and re-adding them one-by-one, but it always ends up telling me something is over-constrained very quickly, even if there are only a few constraints added. 

For some operations, it tells me it can't solve the sketch, but it won't tell me what it can't solve. 

I am at a brick wall. I don't know how to fix this. I shouldn't have to redo the entire project every time I want to make a change... this is a parametric modeler, it should be able to recalculate.

Is there any way to fix this?

[FrankCao]

Hi tima123d,

Thanks for reporting the sketch overconstrain error issue. Could you help attach your model here or send it weining.cao@autodesk.com for us to go on analyze your issue?

Also it would be appreciated if you could record a video or tell us clearly by adding which constraint will you see the overconstraint error.

Thanks,

Frank

[tima123d]

I e-mailed the model to you. I don't think I have any software that can record a video...

-- Tim --

[tima123d]

Here are some screencasts. The first one shows the "over constrained" error.

http://autode.sk/2b3fqh9

http://autode.sk/2bnI5l6

Here is one showing that you can't have a horizontal and vertical constrained line also have a perpendicular constraint:
http://autode.sk/2bnL4dm

This seems simple and redundant, but in a very complicated sketch with a long chain of constraints, one might be stuck because Fusion does not highlight the constraint that is causing the error.

Here is another attempt to make the same sketch, where a chain of constraints fails somewhere in the middle when trying to add a dimension. 
http://autode.sk/2bdi6xy

Please let me know if you need any more information.

I am trying to work around the error by doing all of my calculations in the "Change Parameters" menu and not depending on relations to handle centering or spacing for anything. I've had a little success with that, but it fights me every step of the way.