===== Primitive: Blobby object [Blinn 1982] =====

**Definition**: <m>sum{}{}{b*e^{-a*r^2}-T}</m>

**Call**: hfBlobby(x,x0,y0,z0,a,b,T);

**Parameters**:

x - point coordinates

x0,y0,z0 - arrays of blob centers

a - array of a coefficients

b - array of b coefficients

T - threshold value

**Test file**: [[http://hyperfun.org/blobby.hf|blobby.hf]]