Volume inconsistent density based on cell size

[StasJ]

If you create a volume comprised of 100^3 tightly packed regular cells, the volume density will be much higher than that of a volume of the same size comprised of a single cell.

[carsonbrownlee]

hi Stas, volume density is not a function of world space coordinates. You can achieve this by altering the density scale on the volumetric model.

[johguenther]

That the density of the volume depends on its resolution has been the behavior of OSPRay since the beginning. But I agree that this is unfortunate. We have some ideas to rectify this in a future release (around fall). In the meantime please use densityScale as Carson suggested to counter the effect.

[carsonbrownlee]

Johannes, in ParaView this is handled by altering the scalarOpacityUnitDistance variable on the volume, which by default scales with volume size. In paraviewOSPRay we handle this by altering the density scale to map to the scalarOpacityUnitDistance.