Can anyone tell me how to define the solder paste size for a symbol that is smaller than the pad size?
I have a problem where too much paste is being applied for large component. I still want the larger pad size for heat dissipation, but I don't want that much paste being applied.
It looks like you should be able to "change cream off" on a per-smt basis in the library package editor, and then stick in your own user-defined tCream rectangle...
I would draw a pad of the actual size you want the solder mask. Then add extra copper on the TOP layer. You can draw everything that you would on a PCB into a library part, including regular tracks. (Well, they're not exactly like the tracks you usually use in Eagle because there's no net with an airwire. Just draw lines, rectangles and polygons on the copper layer.) It even flips to the correct layer if you put the part on the bottom of the PCB.
I've also made pads for chips with a large central pad where I don't want too much solder paste. I turned off the cream for the pad and then drew rectangles on the tCream layer where I did want to have paste within the open soldermask.
I'm not seeing any overlap errors. I have Cream deselected for the individual pads. I then draw the smaller shape on the Top Cream layer (31) for the Package. I don't get any overlap errors.