PRT volume spacing

Krakatoa for 3ds Max
1

Is it possible to control the spacing of a PRT volume using a sphere gizmo? what I am trying to do is a voxel effect and I want to change the spacing from a paricular point to the effect dosent suddenly happen.

Thanks

2

No, the Spacing of the PRT Volume is fixed for the whole object - you can animate it over time, but not vary it within the same frame. That being said, you CAN change the spacing of the particles after the distribution using Magma. For example, you can “gridify” a random jittered distribution of particles to form a regular grid: youtube.com/watch?v=Ps1FWER … 240F8FC4E3
(this video uses an ancient version of Magma, but the principles are the same).

The main issue with this approach is that you cannot smoothly vary the grid size over distance - it would produce Streaks of particles as the grid spacing slowly changes between small and large. It looks quite interesting, but it is surely not what you are asking for.
KMX2_Gridfy_Variable_Spacing_Streaks_v001.max (80 KB)

The alternative would be to try to vary the grid spacing by a factor of two along each axis - similar to changing subdivisions. One voxel will be split into 2x2x2 voxels, so the grid would get denser, but never get out of alignment. Not sure if this is what you want either:
KMX2_Gridfy_Variable_Spacing_Subdivisions_v002.max (84 KB)

Showing an image or mockup of what you expect to see would be useful…

The attached scenes are in Max 2013 format.

3

Thanks Bobo ,

I will have a look at these. basicaly what I am doing is the cubify effect where we go from low res (ie few cubes) to a more detailed version. Animating the spacing works great but it happens all at onces so I want was trying to make it a bit more interesting by having some variety in the level of detail so some sections would be have more cubes packed in than the rest.
voxel_upres.avi (609 KB)

4

Here is a scene with Frost that changes the voxel size as the gizmo passes by. The voxels are always twice as large as the previous ones, and the Radius channel is used to control the Frost to match that.

You can of course vary the Radius gradually, but that would produce larger gaps between the voxels. If you start adapting the grid locally, you would lose the grid completely as my first example in the previous post showed (getting radial streaks instead of a grid).
KMX2_Gridfy_Variable_Spacing_Subdivisions_Frost_v003.max (84 KB)