Repopulation Emission

Use this forum for discussions specifically related to the Krakatoa SR C++ API.
For discussion of topics applicable to both the C++ and Py APIs, please use the parent forum.
User avatar
Chad
Posts: 2092
Joined: Tue Nov 22, 2005 9:35 am
Contact:

Repopulation Emission

Postby Chad » Wed Jun 05, 2013 6:28 pm

When I use Repopulation, the Emission doesn't appear to be distributed correctly. I'm getting a LOT more emission than I should.

User avatar
Conrad Wiebe
Posts: 774
Joined: Wed Aug 15, 2007 12:24 pm
Location: Thinkbox Software

Re: Repopulation Emission

Postby Conrad Wiebe » Wed Jun 05, 2013 6:49 pm

Emission is distributed the same way that Density is distributed.
When creating the voxel grid (upon which the repopulated particles are based), each particle contributes to their nearby voxels. For most channels, the voxel values are averaged from the nearby particles, however, for "Density" and "Emission", the voxels contain the value sums of the nearby particles.

Just as a frame of reference, if you define the total emission of the particle set as sum of all the particles' Emission values. The total emission of the repopulation particle set should be on the same scale as the original total emission. They will not be exactly same, but they should scale the same way.
Conrad Wiebe
Software Development Manager
Thinkbox Software

User avatar
Chad
Posts: 2092
Joined: Tue Nov 22, 2005 9:35 am
Contact:

Re: Repopulation Emission

Postby Chad » Wed Jun 05, 2013 9:06 pm

Ah...

Same scale, or roughly the same? I'm expecting the sum to actually be more or less the same, but I'm constantly modifying the emission strength exponent to get the lighting balance back into the image. I haven't checked the emission values explicitly post render (via an exported PRT), but it might be something else going on contributing to the accumulated pixel.

User avatar
Chad
Posts: 2092
Joined: Tue Nov 22, 2005 9:35 am
Contact:

Re: Repopulation Emission

Postby Chad » Thu Jun 06, 2013 4:05 pm

Saved out some PRT's, and with Repopulate on, the Emission channel is unchanged, so the sum is much higher. The density goes way down with Repopulate, and the count goes up, so the net effect is the render is a LOT brighter when Repopulate is on.

User avatar
Conrad Wiebe
Posts: 774
Joined: Wed Aug 15, 2007 12:24 pm
Location: Thinkbox Software

Re: Repopulation Emission

Postby Conrad Wiebe » Thu Jun 06, 2013 4:48 pm

I found the issue. It was my fault.

The issue was that the current download doesn't have the Emission fix that I added. The fix is already in the released Maya version, but I haven't uploaded an SR build in quite some time. Sorry about the confusion.

The attached build should have all the latest changes. So, this should change the look of the Emission channel quite a bit. I'll work on getting an official build out soon.
Attachments
KrakatoaSR-EmissionRepopulationFix.zip
(3.66 MiB) Downloaded 75 times
Conrad Wiebe
Software Development Manager
Thinkbox Software

User avatar
Chad
Posts: 2092
Joined: Tue Nov 22, 2005 9:35 am
Contact:

Re: Repopulation Emission

Postby Chad » Fri Jun 07, 2013 1:02 pm

Wow, that's makes all the difference. Now our interactive renders look very much like the full repopulated ones.


Return to “Krakatoa SR C++ API”

Who is online

Users browsing this forum: No registered users and 1 guest