VDB voxel size from life

Forums Technical Discussion VDB voxel size from life

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Emily Luke: Member; 16 posts; Joined: Oct. 2014; Offline

Nov. 27, 2014 6:34 p.m.

Hey all
I'm trying to get some volumes to grow in size according to their age, from newborn small to old large. Is there an expression I can type into the voxel size parameter that will “just work”?
I've used particles to build my volumes, so we can work with particles here.


Emily Luke: Member; 16 posts; Joined: Oct. 2014; Offline

Nov. 27, 2014 8:13 p.m.

I've got a mathematical expression that i can apply to my problem, basically fixing it. my only problem is that I can't access the $age variable in the vdb from particle voxel size parm. do you guys know how to transfer local variables so that i can access my particle lifetime?


edward: Member; 7734 posts; Joined: July 2005; Online

Nov. 27, 2014 8:18 p.m.

The size of the voxels must be the same for the *entire* volume.


Emily Luke: Member; 16 posts; Joined: Oct. 2014; Offline

Nov. 27, 2014 9:16 p.m.

edward
The size of the voxels must be the same for the *entire* volume.

so you're saying its impossible?


edward: Member; 7734 posts; Joined: July 2005; Online

Nov. 27, 2014 9:18 p.m.

If you want the size of voxels in the same volume primitive to be different, then yes, that is impossible.


PradeepBarua: Member; 443 posts; Joined: Sept. 2012; Offline

Nov. 28, 2014 1:18 a.m.

You can fake this:

Attachments:
Grow_volume_over_time.hip (213.8 KB)


Emily Luke: Member; 16 posts; Joined: Oct. 2014; Offline

Dec. 5, 2014 5:50 p.m.

edward
If you want the size of voxels in the same volume primitive to be different, then yes, that is impossible.

i was able to do it using pscale. not impossible.

Attachments:
nrt08_fx_v015.hipnc (3.9 MB)


edward: Member; 7734 posts; Joined: July 2005; Online

Dec. 6, 2014 1:24 a.m.

I think you're confusing “voxel size” with “number of voxels corresponding to a particle”.


anon_user_37409885: Member; 4189 posts; Joined: June 2012; Offline

Dec. 6, 2014 2:03 p.m.

A great way to analysis Vdb is with ‘Vdbvisualizetree’ node. It allows you see the volume structure quantifiably.

Attachments:
Screen Shot 2014-12-07 at 8.00.21 am.png (602.5 KB)

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