setting value per voxel in VEX from point level

[legomir]

Is possible to setting value of voxel in vex like this way:

 

density[j][k] = some_value;

 

or I will have to use python or HDK?

 

Edited October 29, 2015 by legomir

[Guest mantragora]

Don't have time to look at this more, but in VolumeVOP look at

ix, iy, iz

indices, to get where you are, compare it and set density value if True etc.

[legomir]

Maybe name of this topic is a little to generic so be precisely i want access to setting voxel value by it indexes. Is this possible in VEX in efficient and elegant way or rather i must be using HDK or Python for solve this problem 

Edited October 29, 2015 by legomir

[Guest mantragora]

From help:

ix, iy, iz

Voxel indices. For Volumes these ranging from 0..resolution-1. For VDBs, they refer to the absolute location. Use volumepostoindex with the orig to get the lowest value of the ix,iy,iz for the current VDB.

so this:

vector res = volumeres(geoself(), 0);
if (@iy == (int(res.y / 2)) && @iz == res.z / 2)
    @density = 10;
else @density = 0;       

wil make stright density line.

Or do you rather want Voxel center?

vector pos = volumeindextopos(geoself(), 0, set(@ix, @iy, @iz));
addpoint(geoself(), pos);

Otherwise I'm not getting what you are asking about.

Image doesn't help. What you show there? Couple voxels from which you want the middle one? Center of a voxel?

PS. You can try do the same with HDK, but I don't think that C++ will be more elegant than VEX. It will require a lot more lines of code for sure.

Edited October 29, 2015 by fântastîque Mântragorîè

[f1480187]

The question is about setting voxel's density in o(1) time, without iteration. For example, if he already iterating while iterating.

setprimattrib(0, "attrib", @primnum, value);             // For primitives we use this.
setvoxeldensity(0, volumeprimnum, @ix, @iy, @iz, value); // For voxels we want that. There is no such function.

Edited October 29, 2015 by f1480187

[legomir]

 

The question is about setting voxel's density in o(1) time, without iteration. For example, if he already iterating while iterating.

setprimattrib(0, "attrib", @primnum, value); // For primitives we use this.
setvoxeldensity(0, @ix, @iy, @iz, value);    // For voxels we want that. There is no such function.

Yep. This is exactly who i want to do Sorry for my unclear explanations

[ranxerox]

 what is it that you actually want to do ?  If it's actually a question about performance you are going to be better off sticking with the volume VOP/wrangle paradigm as that is easily multithreaded.

 

 -G

[legomir]

I try compute custom weighting function for every step on simulation for nearest voxel around point.

[ranxerox]

could you do it in reverse ?  Ie.  for each voxel calculate your weight to the point in question ?  It does seem odd that there isn't a vex function to set specific voxels.

 

 -G

[legomir]

Is not possible to do this in this way(weighting by particle), but volume vop and point vop are building on cvex context so maybe is some way to do this?

[Guest mantragora]

Check this file. Not too much optimized, but I hope that this is what you were looking for.

for_legomir.hipnc

Edited October 30, 2015 by fântastîque Mântragorîè