Dynamic paint. Displacement only when origin intesects canvas

I made a crab that has to dig into the sand. The crab has an armature and a brush modifier with mesh volume as paint source. The sand has a canvas modifier with displacement surface type. The problem is that the canvas is only modified when the origin of the crab intersects the canvas, so the canvas it is not modified by the legs. I tried with another objects -sphere, cube- as brushes and they work fine.

on the brush objects “dynamic paint source” tab what type of brush is it, I believe mesh volume+proximity is the setting you need, also ensure your modifier stack on the brush object is in the correct order, (try shuffling them around till it works)

other than that you could make a dummy particle hair system which is not rendered, and literally use this as a brush this will allow you a nice level of control on where you paint, as you can set the radii of the paint distance. or use longer or shorter “brush hairs”

I just read in another thread that deformed meshes cannot interact with pysics sims. The particle system is the best option and very realistic.

Thank you, Exile420, i was really stuck…