Driver averaged value confusion

Hello all,

I have encountered a problem that may be normal as far as blender is concerned, but confuses the hell out of me.

I add a plane, then move it away from the origin and add a location driver. When I go into the graph editor and change the driver type to “averaged value” the object jumps back to the origin. Why?

I want to be able to have a bone drive another object from a particular location and not relative to the origin (0,0,0). How would I go about doing this?

Much thanking

Do you have a driver set up when you switch to ‘averaged value’? If you haven’t entered the name of the armature & the bone that should be driving the location of the plane, then blender has no value to assign to the location. So it assigns a value of 0. In the properties panel of the graph editor, there is ‘show debug info’ checkbox, clicking on that will show the value of the driver.

If you have a plane at x,y,z = 5 and you want to drive it’s location, you’d have to use ‘scripted expression’ and in the ‘expr’ box, enter an expression. The expression would be something like ‘5 + var’, where var would be the name of the variable, by default blender assigns ‘var’ as the name to all variables.

See the attached .blend file. In it, there is a plane at x,y,z = 5 and an empty at 0,0,0. Move the empty around and the plane is always 5 b.u. away from the empty…



driver_example.blend (325 KB)

Thanks for your reply it helped solved the problem, and gave me a brief insight into basic scripting, something I’d been putting off, but I see now that I need to get script happy.