1. ## Arc Length dimension???

Anyone seen this before?

In an assembly layout I need to dimension an arc length.

When I select the arc length dimension the value is correct.

But as soon as I place the dimension the value changes to what seems to be the short side of the arc(the part of the circle that isn't there)

I have done this on many other assemblies with no problems and I can't seem to get it to happen again. But in this particular assembly, no amount of fiddling fixes the problem

2. I don't necessarily have a direct solution for your problem but would like to offer this up as it may help you figure out what's wrong:

If you're saying that the 862.861 dimension in the first pic is correct, it seems unlikely that the 638.372 dimension in the second pic is the missing part of the circle. Just eyeballing, I'd put the missing part in the 400 range.

Also, I don't know if there's more to the sketch that's not shown but relations #14,16, and 22 seem unnecessary. At least, I was able to fully define a similar sketch without making those entities coincident with something else. It took me 4 tangent relations, 2 radius dims, 1 coincident relation, 1 arc length dimension, and 1 linear dimension to define the sketch. The only coincident one was to make the center of the big arc coincident with the origin. That might be part of the problem.

Hope this helps...
AP

3. Forgot to say that the dimension becomes a driven dimension that I use in an equation to determine the v belt length.
I will have a look at the relations

4. i think some where , maybe in more properties you find , min or max

5. This is very similar to something I've been trying to do as well. I'm using circles and lines to model a flat belt path, and in many cases the belt wraps around the pulleys more than 180 degrees. I would like to show a dimension for the degrees of wrap but SW doesn't want to display more than 180 degrees. It doesn't seem to want to do the "reflex" angle, only "obtuse" or "acute".

I figured out that you can create the angle as acute or obtuse first, then dimension it, and THEN move it to be the reflex angle. That's a pain though and shouldn't be necessary. I would be VERY happy if there was a way to dimension reflex angles.

C|