[Bf-cycles] [GSoC 2018] Feasibility of greater integration of OpenVDB into Cycles

[Brecht Van Lommel]

Hi Geraldine,

Blender indeed supports OpenVDB as a file format for baking smoke
simulations, but nothing else.

We indeed want to have an OpenVDB backed volume object in Blender. But it's
a big project that touches a lot of areas, and we prefer projects that are
well defined and can be finished within the GSoC timeframe. We shouldn't
have a Blender version that supports volume objects but has no way to
render them. So I think it makes most sense to add Cycles rendering support
first, because it's pretty much a required step in adding a volume object.

Cycles tiled 3D image storage is important to support VDB files properly,
since being able to store sparse volumes is a big feature of OpenVDB. Basic
reading of OpenVDB files into 3D images is a relatively small project.
These projects can potentially be finished much faster than the GSoC
timeframe, it depends on the experience of the student. Starting a Blender
volume object as an optional third step in the remaining time makes sense
to me.

Regards,
Brecht.


On Thu, Mar 22, 2018 at 3:05 PM, Gg Cc <gsc97531 at gmail.com> wrote:

> Hello everyone!
>
> I am Geraldine Chua, a prospective GSoC candidate, and although I am a
> little late to the game, I would really love to be able to help work on
> Cycles over the course of this summer :).
> In regards to my project, I would like to enquire about the feasibility of
> fully integrating OpenVDB into Cycles. One of the tasks mentioned under the
> Volume Rendering potential ideas list is the "Direct reading of OpenVDB
> files as a Cycles 3D image, to render volumes generated by other software."
>
> Right now, it seems like Blender can already read and write (but not
> edit?) smoke volumes (but not other volumes?) as OpenVDB files (
> https://wiki.blender.org/index.php/User:Kevindietrich/OpenVDBSmokeExport).
> There are also various other integrations done over the years such as one
> attempted back in GSoC 2013 (although I cannot tell how far Jehuty managed
> to finish) and the rest of Kevin Dietrich's work.
>
> However, from this forum post (https://blenderartists.org/fo
> rum/showthread.php?433900), as well as a few others, it seems like a
> quite a few people want much greater support for OpenVDB. Perhaps instead
> of doing these 3 unrelated (although all interesting!) tasks for Volume
> Rendering, I could focus on extending or even finishing the OpenVDB
> integration started by Kevin Dietrich. This would be a much more focused
> project, and I think one fully-fledged project, as opposed to a few spread
> out tasks, might be better for the community who will get a fully-fledged
> new tool.
>
> Some ideas of tasks that can be done:
>
>  - Revisit and complete Kevin Dietrich's unfinished projects such as the
> implementation of a Volume Object Primitive or the Particle Mesher Modifier
> (https://wiki.blender.org/index.php/User:Kevindietrich)
>
>  - Integration of other features of OpenVDB such as conversion tools,
> transforms, etc. (http://www.openvdb.org/about/)
>
>  - Refactoring of current Volumes functions in Cycles to work with the
> OpenVDB format
>
> I would like to ask from those who are much more experienced than me in
> volumes development:
>
> 1. Does this project contradict any current plans or goals set for the
> Blender architecture? Is OpenVDB integration a goal of Blender's?
>
> 2. Is this a project that is of actual benefit to the Blender community?
> Or is the original requirement of only OpenVDB import/export what is
> actually needed and  would you rather I focus on trying to also accomplish
> the other 2 volume rendering tasks?
>
> 3. Would you estimate that this project is feasible, i.e. the most useful
> features can be implemented in 12 weeks?
>
> Thank you for taking the time to read my questions and I hope you can
> provide some of your insights and feedback on this proposal :). I know that
> the Blender development community is a quite busy right now with the
> upcoming Code Quest, so thank you for taking the time to help me on this.
>
> Best regards,
> Geraldine Chua
>
>
> _______________________________________________
> Bf-cycles mailing list
> Bf-cycles at blender.org
> https://lists.blender.org/mailman/listinfo/bf-cycles
>
>
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