effect template tools

I highly suggest you look at maptool's template tools. It allows a quick placement for area of effect spells (radius, cone, etc) with measuring built in (it counts the radius size in real time as you are extending the effect). This tool is extremely useful for figuring out how big the fireball explosion will be, etc.

Sounds like such a thing wouldn't be system agnostic. That is to say, you'd have to build in system-specific templates--something Roll20 is not about to do.

Well, the example I think of is a user would select "draw a radius" and as you were drawing it (and it snapping to grid), it would measure the size... so you can see the extents of a circle radius in increments of 5. I noticed roll20 does have different measurement rules when you set up a map, for D&D 4.0 vs Pathfinder/3.5, for example. I don't necessarily see this as specific to a game system though, if its just a generic radius with a number reporting the real-time measurement for how big it is as you are drawing it. Although maybe I am mistaken. Thanks.

Ah, I see what you mean. I think I misunderstood your post. You're basically asking for a radial measuring tool? That could be handy.

Radius, cone, maybe a few other common generic patterns or shapes?

Just an idea: you can use the art tools to make templates. I have used the polygon function to set up cones and the circle function to set up radius effects. - Gauss

<a href="http://community.roll20.net/discussion/3409/pointer-target-tokens-for-roll-20-download-link-included" rel="nofollow">http://community.roll20.net/discussion/3409/pointer-target-tokens-for-roll-20-download-link-included</a> You could also use what I have done as an example and make a deck of templates that players could click through and then draw and drop onto the map to move around.