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hey
just messing around with emfluid and openvdb - amazing!

I also run into some questions: Like on the pic, there is that green line around the .vdb. Similar to the outline, Arnold creates when there is alpha.
But how can i remove/avoid that? Is that an arnold thing or caused by openVDB?

Also I wonder, where the details are. The emfluid5 renderer has some more cauliflower details, here they are gone.

And the last, but most important question: what means "keyerror: map" ? Its caused by openVDB while trying to read and cached .vdb.
It works all till frame 66, after that I cannot read any file and in my viewport the openVDB-Cube disappears.
Could it be a filesize problem?
Its exactly on that frame, where the files become bigger than 2gb...

edit: also gives me the error : "Lookup Error: Cannot read grid. Grid type"

edit2: https://groups.google.com/forum/#!msg/o ... JScvQhC9wJ
seems, that is a similar problem?

Try calling openvdb::initialize() first.

Is it possible to do that in SI?

it actually seems to be a file size problem.
Did restep with different cell size and it worked.
I ll simulate again with not so high steps (1,5) and enable the option tiled... does that mean, it tiles the file?
And if the file size is the problem, any way to fix that?

thx!

>>Btw, would be great to know if there is a manual or kind of some help on this great plug in?
Sorry, right now i dont have enough time to make some tutors, but that plugin is still on my plans to push it towards 1.0 stable release with some kind of intro tutors. If you have any specific questions please ask here.

>>So wondering if the OpenVDB can exchange much more than fluids (smoke), is a kinda of alembic? but that exports all?
VDB holds voxel data, that means you have native support of all voxel-based fluids, and you can also hold any geometry as a certain value across these voxels where the original polymesh has intersected it. This way you have very smoothed mesh representation, without sharp details(even if you crank up voxel counts to insane values ) so the answer is rather no than yes, you cannot transfer polymeshes via vdb.


>>I also run into some questions: Like on the pic, there is that green line around the .vdb. Similar to the outline, Arnold creates when there is alpha.
But how can i remove/avoid that? Is that an arnold thing or caused by openVDB?

this is usually is a result of negative density, try to clamp the vdb sclar reader value with min treshold 0 before put it to volume collector.

>>Its exactly on that frame, where the files become bigger than 2gb...
It may be a problem, i have "Try calling openvdb::initialize() first." called everywhere openvdb is ( and thats why you can work till 66 frame ).
Can you share please one of there >2gb vdb files ?

>>Also I wonder, where the details are. The emfluid5 renderer has some more cauliflower details, here they are gone.
Thats depend of emrendered, can it have some render-time upscale techniques ?

Hey, thx for your answer.

>>this is usually is a result of negative density, try to clamp the vdb sclar reader value with min treshold 0 before put it to volume collector.

super, will try that!
(edit: its working with the scalar change range)

>>It may be a problem, i have "Try calling openvdb::initialize() first." called everywhere openvdb is ( and thats why you can work till 66 frame ).
Can you share please one of there >2gb vdb files ?

yea, will upload a file and send the link per pm


>>Thats depend of emrendered, can it have some render-time upscale techniques ?[/quote]
dont understand that - do you need a render of the same scene rendered with emfluid5 renderer?

>>Thats depend of emrendered, can it have some render-time upscale techniques ?[/quote]
dont understand that - do you need a render of the same scene rendered with emfluid5 renderer?

i mean that emrender may add some procedural details like waveletturbulence on rendertime, while arnold renders raw low-res volume grid. But i dont know how emrender is doing its work so the real problem can be in something different.

>>i mean that emrender may add some procedural details like waveletturbulence on rendertime, while arnold renders raw low-res volume grid. But i dont know how emrender is doing its work so the real problem can be in something different.

Ah okay, going to ask that in the group.

edit: Eric wrote:

Any way, the emFluid5 renderer does not create any additional details, it renders the grids "as is".

Thanx Core for reply me ;)

@sant0s

i think the emfluid preview looks like as almost solid and thus produces very sharp shadows and shapes while the arnold's render is much more "volumy" ( take a look at the borders of the mushroom ) which tends to smooth out some micro-scaled details. Try for example to crank up densities for light and camera absorbtion to see if it will result in more shaped look.

thx mr. core - that is giving some realy nice details. freakin'...

very nice sant0s , so on the left emFluid and on right Arnold?

is both arnold.
left with mr. cores hint to increase densities multiplyer, the right side is the same but muliplyer left by 1.

edit: but its all simulated with emfluid5.

I have a problem with the Mentalray shader, whatever setting I try the cloud is not visible in the alpha, any suggestions what I could be doing wrong?

Cheers, Wim

hey
have a strange problem.
when i render the vdb cloud with the region tool or do a ../Render/Preview, I get the result I need.
But when I render the current pass or current frame, I get a totaly different result like shown on the images.
any idea, what that could be?
its rendered with arnold and the region tool is set to "use current pass options".

thx alot,
sant0s

hmm, got it ^^

in pass options under output format i had RGB instead of RGBA. kleines dummerchen

I just installed your OpenVDB stuff but have run in to a snag - I get this error when doing a renderregion on your cloud demo scene:

' WARNING : [arnold] node "VDBVolumeShaderSimple_ai" is not installed
' ERROR : [sitoa]: Unable to load VDBVolumeShaderSimple_ai from the Arnold plugins (first occurrence: Sources.Materials.DefaultLib.Scene_Material.VDBVolumeShaderSimple_ai)

Upon Inspecting the Plugin Manager I can see that VDB_shaderDefs_ai.pys has a red triangle and checking its properties it says 262$This script plug-in contains erors and could not be loaded: <path: "path to workgroup installation"

I do have vcredist_x64 installed. Could this be caused by the annoying tbb.dll conflict with Arnold?

Cheers
Morten

hey morten,

correct sitoa version? I think, it may be caused if version is over sitoa 3.0.0.