Problem 1294

Hello,

I noticed that the points that are generated via the GetPointOnSurface() method are not distributed uniformily for several solids (e.g. G4Tubs, G4Sphere).
For example G4Tubs: As rRand (like phi, but that's o.k.) is generated just using a uniform distribution the points on the bottom and top of the cylinder cluster around r = 0. To obtain a uniform distribution I'd suggest to calculate the angle phi and radius r for the cylinder using the uniform (0,1) distributed random variables v1, v2 as follows

phi = v1 * (phi_max - phi_min) + phi_min (as already done by RandFlat::shoot(fSPhi, fSPhi+fDPhi))
r = sqrt(v2 * (Rmax^2 - Rmin^2) + Rmin^2))

and change the GetPointOnSurface() methods for the other solids accordingly (if possible). Or is there a reason that the points are not generated uniformily?

Thanks in advance,

Tobias