Mitsuba Exporter

Discussions concerning plugins for SOFTIMAGE©
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TwinSnakes007
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Re: Mitsuba Exporter

Post by TwinSnakes007 » 26 Jan 2013, 03:31

No pictures this time, but added support for:

Homogeneous and Heterogeneous Volumes
Cameras and Camera Shaders
Lights and Light Shaders

forton
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Re: Mitsuba Exporter

Post by forton » 31 Jan 2013, 22:58

Need a beta tester? :o3

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TwinSnakes007
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Re: Mitsuba Exporter

Post by TwinSnakes007 » 01 Feb 2013, 00:39

Sure do. Waiting for Bug repository to be setup and then we'll put this puppy thru the paces.

-TS-

P.S. - Working on GridVolume at the moment. This will allow you to define Volume shapes using SI PointClouds & ICE.

GridVolume is how this was done:

[rimg=800]http://www.mitsuba-renderer.org/images/gallery/scarf-flakes.png[/rimg]
Last edited by TwinSnakes007 on 07 Feb 2013, 18:09, edited 1 time in total.

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TwinSnakes007
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Re: Mitsuba Exporter

Post by TwinSnakes007 » 07 Feb 2013, 18:07

Adding PointCloud generation of GridVolumes has been tough. The difficult part about adding this feature was not breaking the existing support for ConstVolume as well.

I had to rework the Heterogeneous shader definition to support both ways, and I think I'm good to go now. I thought this would take a day to do, its been like over a week.

I hope to post a video tonight of setup and result.

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Tekano
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Re: Mitsuba Exporter

Post by Tekano » 07 Feb 2013, 18:11

sounds awesome, and incredibly complicated! looking forward to seeing your video.

how are gridvolumes being supported via Softimage? what format are they in to start with?
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TwinSnakes007
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Re: Mitsuba Exporter

Post by TwinSnakes007 » 07 Feb 2013, 18:47

Tekano wrote:how are gridvolumes being supported via Softimage? what format are they in to start with?
A GridVolume is a Volume composed of "cells" along each axis x,y,z. Each cell can have 3 properties: Density, Color, Orientation. So this data can easily be defined via PointClouds in Softimage. The hard part was coming up with a way to do that, so that its reasonably intuitive to an SI user.

So, after several different approaches, the cleanest way I could come up with is a combination of:

* Use the particle "color" attribute to set the cell Color property, the particle "mass" attribute to set the cell Density property, and the particle "force" attribute to set the cell Orientation property.

* Require a "Generate 3D Point Grid" node to be present on a ICE Tree. I read the values of this compound to set the x,y,z resolution of the GridVolume and to error check against the NbPoints attribute.

So, with that setup, you can do anything you want to the PointCloud, except one thing - Delete a point. The number of particles described by the ""Generate 3D Point Grid" node must equal the number of points in the PointCloud. Other than that limitation, you can set the values of those 3 properties by any means available to you in SI.

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TwinSnakes007
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Re: Mitsuba Exporter

Post by TwinSnakes007 » 07 Feb 2013, 18:58

For instance, you could render this in Mitsuba.


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Tekano
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Re: Mitsuba Exporter

Post by Tekano » 07 Feb 2013, 19:01

oh interesting, ok thats how I imagined it being implemented with ICE only, but was thinking about the grid format itself on how to bring the grid volume data from another format like .Bafl or field3d or http://www.openvdb.org/ or maya fluids or houdini bgeo etc.

so for example if we managed to get the grid data into softimage from other formats and changed each cell to be a particle and reassign the density - mass etc we should be able to render it in Mitsuba!

:D
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TwinSnakes007
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Re: Mitsuba Exporter

Post by TwinSnakes007 » 07 Feb 2013, 19:13

Tekano wrote:but was thinking about the grid format itself
Its a very simple binary format. You describe a header, and then write the data.

Here's a C# implementation of the GridVolume format.

GridVolume.cs

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Tekano
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Re: Mitsuba Exporter

Post by Tekano » 03 Apr 2013, 11:37

any news on this twinsnakes? looking forward to trying this out for sure
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TwinSnakes007
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Re: Mitsuba Exporter

Post by TwinSnakes007 » 03 Apr 2013, 15:59

I'm still pluggin away at it. I had no idea ICE RenderTree attributes would be this tough to incorporate into the code base. They have been a pain. Basically, everything can have an ICE tree!

I've got some code working that detects an ICE Attribute and validates that it has ICE data (attribute not set to "Use Default Value"), so I'm pretty close.

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Tekano
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Re: Mitsuba Exporter

Post by Tekano » 03 Apr 2013, 16:33

if you are having problems implementing ICE attributes in your code you should definately post questions, maybe someone has been there before and can help you!
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Mathaeus
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Re: Mitsuba Exporter

Post by Mathaeus » 03 Apr 2013, 16:59

...or you can look at this from another side. At least from what I heard, this issue seems to appear again in SI 2013, global score of working-not working seems to be fifty-fifty, for out of the box renderer. So, few attributes more or less, who cares :)

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TwinSnakes007
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Re: Mitsuba Exporter

Post by TwinSnakes007 » 03 Apr 2013, 19:16

Mathaeus wrote:...or you can look at this from another side. At least from what I heard, this issue seems to appear again in SI 2013, global score of working-not working seems to be fifty-fifty, for out of the box renderer. So, few attributes more or less, who cares :)
I'm not sure I understand what the bug is? Is it that the reading of ICE attributes is not consistent?

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Tekano
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Re: Mitsuba Exporter

Post by Tekano » 03 Apr 2013, 20:00

ha well in Matheus's case the bug (between scanline and rasterizer not having same values for attributes) is mute... because we will be rendering attributes with Mitsuba! :-bd
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Mathaeus
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Re: Mitsuba Exporter

Post by Mathaeus » 03 Apr 2013, 21:07

TwinSnakes007 wrote:
I'm not sure I understand what the bug is? Is it that the reading of ICE attributes is not consistent?
Yeah, sometimes happens, that renderer reads ICE tree 'partially' - what you see in viewport, doesn't appear into renderer. It could be worse than just wrong reading of color attribute. Sometimes, reason is NaN in ICE (still solved by ICE, don't know how). sometimes, it's not. Form my knowledge, it's not only with Mental Ray, but integration with MR seems to be champion in errors.

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