Sketch problems - over constraint

[JYZMT]

Help,

Can anyone have a look at the attached file and tell me where I'm going wrong? 

Variable X and Y lock down?????, it gives me a red dimension error. I can't see why they are locked? they should not be? 

[Anonymous]

@JYZMT

After opening your file, I got this:

-> "Modify" -> "Compute All" fixed the problem.

[JYZMT]

Thanks. But why is it doing it. When ever I make changes to the overall dimension, the thing seams to fall over. It must be the why I constrained the sketch, but can't see where.

[JYZMT]

I can get the width to work now, and I can get the height to grow parametrically, but as soon as I drop the height, it freezes up.

Its something to do with the semi circles because with out them it works fine. Why would they constrain it?

[TheCADWhisperer]

Before I spend significant time on this - can you give a bit of information on why you are up to dimension d670 and some information about your Design Intent?

[JYZMT]

ah yes... d670. This is because previously I had a large complicated model. Arrogantly, I did not bother playing with the key parameters early on because I thought it would all work fine. I got miles down the road, tried changing a few key things towards the end and it got very messy. I've spent 3 days unpicking the whole thing trying to find out whats constraining it. I've stripped everything back, but its the same file. 

The semicircles are because the object is being CNC pocketed, and I was looking to include the dogbones in the original sketch and extrusion, rather than try and add them all later. 

Thanks

[TheCADWhisperer · Accepted solution]

Imagine the detritus left behind by deletion of so many trials.  Lots of 1s and 0s the software wasn't sure if it should retain or not.

I consider my first attempt (or 2 or 3) to be only an exercise in understanding the geometry.  Then I create a clean and robust model.

I have found that it is almost always faster to start over from scratch using what I learned from earlier attempts than to try to put lipstick on a pig.

Interesting sketch behavior though....

[eellenburg]

Replace the arcs with circles and you can resize up or down without errors.

[JYZMT]

Thanks. So you think its just because of the history of the file? I'll start afresh and see how far I get. 

Do you know a why to grab parameters from another file? Other wise I have to set them all up again. 

Thanks

[TheCADWhisperer]

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@JYZMT wrote:

... Other wise I have to set them all up again. 

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I only saw a handful?

Also, I would make use of obvious symmetry about the origin.

[JYZMT]

Thats because I stripped them all out when I stripped the file back. I guess there is no way to import them then?

[TheCADWhisperer]

There might be - I don't know.

I don't use Fusion - I use Autodesk Inventor where it is easy to export/import parameters with Excel.

[HughesTooling]

There's a parameter IO plugin on the app store.

https://apps.autodesk.com/FUSION/en/Detail/Index?id=1801418194626000805&os=Win64&appLang=en

[JYZMT]

Thanks. I'll try and rebuild from scratch and let you know how it goes

[JYZMT]

I re built in a fresh file, and it does indeed seam to work. Annoying I've lost 3 days to a bug, but lessened learned. Start fresh every time.

[JYZMT]

And now its happening again. Something happens when you use semicircles, with coincident points and fixed diameters. I can't understand a logic behind this. Can anyone from auto desk explain why the model is being constrained? Thanks

[JYZMT]

It seams ok with circles, as suggested earlier, but not with semi circles.