i am running a student version ov maya ‘09 and although my geometry is selected (for example a nurbs sphere 6,30,30) the scupt tool does change over to the brush, but reguardless of brush size or diameter, it shows only a red circulet with a scuplt axis but will not sculpt the geometry of the object reguardless of which tool(push,pull...ect...ect) is selected. i have reset the tool several times with to no avail.  yes i am very new to maya and am taking the courses but nothing in those courses relates to why it is not working....HELP PLEASE...I AM LOSING MY MIND

What is the ‘opacity’ and ‘max. displacement’ values of your sculpt geometry tool set to?
Screen shots of your object might also be helpful…

n8skow [FA]

I assume that 6 is the radius of your sphere, and 30, 30 are the sections and spans, respectively.  This is a fairly large sphere. 

I’d first delete the construction history of the sphere, sometimes this gets in the way.  Make sure that the sphere is selected when you go to brush it (you probably have, because you wouldn’t get the circle if you hadn’t). 

Remember that the tool works on vertices - if you are not brushing directly over a vertex you’ll get no displacement. 

N8 is asking a good question - the “Max Displacement” is the maximum amount a brushstroke will displace a vertex (in scene units) - and the “Opacity” is how many times you have to go over the same vertex in order to reach the max displacement.  It’s like an airbrush - the maximum coverage would be “1” (Opaque) but if the opacity is set to 0.2, you’d have to go over the same spot five times (on a single click) in order to achieve that 1. 

The default Max Displacement and Opacity are both “1”, if you have a radius of 6, I suggest that you increase the Displacement.  Try 5, just to see.

You also need to pay attention to the resolution of the object.  In order for the sculpt geometry tool to work, it needs to pass over a vertex (polygonal modeling) or the cvs (nurbs modeling).  If you are for instance are trying to sculpt in the middle of a face or a nurbs patch it won’t work.