Circumfrance Dimension, how to do it?

[MattG]

I am trying to dimension a circumfrance distance and/or a arc length.

Reason being I need to figure out the distance between lights on a circle truss for various reasons. This is somewhat spotilght based. Is there a way to do this? What I have is a 30' OD circle that has lights every 45 degrees. My first thought was to draw the a arc from light 1 to light 2 and dimension the arc, this works, but I then have a whole ton of arcs I need on my drawing for nothing more then dimensions, and I have to draw them all in. I really don't want to do that, anyone have any thoughts?

I also understand the math for this isn't too hard to work out and I have already done it in the literal application. It is more the process as this is something that comes up often.

My wish would be a dimension tool that had a mode for this. Where I could select a center point then a point a and then a point be using the distance of your center to point a as your radius and kept that in mind when selecting point b limiting you to stay on your radial path if that makes sense.

my thoughts on it

Edited May 27, 2010 by MattG

[bcd]

Good suggestion - a linear dimension is defined by two points - a radial dimension could similarly be defined by three.

There is the option to Modify>Covert line to dimension but this only provides the angle between two radii, rather than your required arc-lenght.

The best I can identify today is placing your arcs in a hidden class. At least this way they do not clutter your drawing, It can be turned off and the dimension will remain visible. Perhaps there are more elegant solutions.