New volume object type #73201

Status: Initial part of milestone 1 merged into master.

Team

Commissioner: ?
Project leader: @brecht
Project members: @sebbas @JacquesLucke

Description

Big picture: Volumes need their own native datablock type, so Blender can support other use cases like rendering OpenVDB files or procedurally generating volumes.

Use cases:

Existing use cases (smoke modifier on mesh).
OpenVDB file rendering.
Procedurally generating volumes (part of everything nodes).

Design:

New Volume datablock (similar to Mesh) with an OpenVDB volume data structure with an arbitrary number of attributes.
Rendered by Cycles and Eevee, first as dense volume as we have now, and later with native sparse volume rendering.
Volume objects would have modifiers (add resolution detail, fluid domain modifier, ...)

Engineer plan: ?

Work plan

Milestone 1
Time estimate: 10 workdays to complete implementation, 5 for review/docs/bugs.

Completed for merge into Master.

New volume object data type, based on OpenVDB grids
- Support reading OpenVDB files from disk
- Add New material adds principled volume material
- Solve problem with not enough FILTER_ID bits
- Show warning when loading VDB points file
- Auto rotate object from Y-up to Z-up when file was written by Houdini?
Rendering of dense grids
- Cycles
  - Basic integration
  - Use principle volume as default material if no material exists
  - Support different transform per grid
- Eevee
  - Basic integration
  - Use principle volume as default material if no material exists
  - Support rotation/shear in transform
  - Shader code generation for arbitrary number of grids
  - Support different transform per grid
- Workbench
  - Basic integration
  - Control over which grids to display (active grid only by default?)
  - Use workbench object color settings
  - Density scale setting
  - Figure out why density changes with object scale
- Add option to specify volume density in object space
- D1777: Cycles: implement per shader volume step size.
Viewport drawing and selection of volume bounds
- Wireframe bounds display of tree nodes (at intermediate or leaf levels)
- Points display type, that shows one point per coarse/fine node
- Selection support (based on wireframe bounds?)
User interface
- Open file browser immediately from Add menu
- VDB / volume file type in the file browser
- Drag & drop VDB files into 3D viewport
- Finalize properties editor UI layout
Python API
- Grids
- Transforms
File loading
- Error reporting
- On-demand loading
- Global cache
Dependency graph copy-on-write integration
- Refactor mesh runtime storage to be reusable by other objects types
- Automatic instancing for objects without modifiers, like meshes
- Fix runtime backup memory leak
Volume frame sequences
- Settings to use single volume or sequence, start, length, offset
- Dependency graph integration
- Auto detection of sequences when loading file

Viewport
Time estimate: ?

Viewport selection by rendering fine boxes when drawing for selection (current volumes can't be selected except through the outliner or the origin point if visible)
Workbench: additional viewport display options
Option to use lower resolution volume for viewport display

Rendering
Time estimate: ?

Option to pick byte/half/float precision for 3D texture in Cycles and Eevee
Eevee/workbench
- Share textures in global volume cache
- Preserve batch cache through display setting changes
- Sparse grid rendering using NanoVDB
Cycles
- Optimize mesh bounds creation by using OpenVDB tree
- Sparse grid rendering using NanoVDB (D8794)
- Share 3D images like global volume cache
Auto complete grid names in shader nodes

Modifiers
Time estimate: ?

Mesh to Volume modifier
Points to Volume modifier (from PointCloud or Mesh) as a node
Volume to Mesh modifier
Displacement modifier (D9075)
Texture modifier with blending modes (add, multiply)
Filter modifier (dilate, erode, blur, sharpen, ...)
Fluid Simulation modifier, replacing the current modifier on meshes for gasses (not liquids)

Other

Mantaflow: output OpenVDB files with multiple grids and standard grid names
VDB tree/voxels API using pyopenvdb
File packing
File saving
- Python API
- Operator in the UI (unclear where still)
Grid metadata: show in properties editor
- In the spreadsheet
Support other applications overwriting OpenVDB files open in Blender (#75901)
Volume edit mode and file saving
OpenVDB level sets, perspective transform
Cluster support (multiple grids with the same name and different transform) (#86313)
VDB files with modifiers are reloaded whenever parameters are changed, revisit this (memory vs. performance)

Relevant links:

**Status:** Initial part of milestone 1 merged into master. --- **Team** **Commissioner:** ? **Project leader:** @brecht **Project members:** @sebbas @JacquesLucke **Description** **Big picture:** Volumes need their own native datablock type, so Blender can support other use cases like rendering OpenVDB files or procedurally generating volumes. **Use cases**: * Existing use cases (smoke modifier on mesh). * OpenVDB file rendering. * Procedurally generating volumes (part of everything nodes). **Design:** * New Volume datablock (similar to Mesh) with an OpenVDB volume data structure with an arbitrary number of attributes. * Rendered by Cycles and Eevee, first as dense volume as we have now, and later with native sparse volume rendering. * Volume objects would have modifiers (add resolution detail, fluid domain modifier, ...) **Engineer plan:** `?` **Work plan** **Milestone 1** Time estimate: 10 workdays to complete implementation, 5 for review/docs/bugs. Completed for merge into Master. - [x] New volume object data type, based on OpenVDB grids - [x] Support reading OpenVDB files from disk - [x] Add New material adds principled volume material - [x] Solve problem with not enough `FILTER_ID` bits - [x] Show warning when loading VDB points file - [x] Auto rotate object from Y-up to Z-up when file was written by Houdini? - [x] Rendering of dense grids - [x] Cycles - [x] Basic integration - [x] Use principle volume as default material if no material exists - [x] Support different transform per grid - [x] Eevee - [x] Basic integration - [x] Use principle volume as default material if no material exists - [x] Support rotation/shear in transform - [x] Shader code generation for arbitrary number of grids - [x] Support different transform per grid - [x] Workbench - [x] Basic integration - [x] Control over which grids to display (active grid only by default?) - [x] Use workbench object color settings - [x] Density scale setting - [x] Figure out why density changes with object scale - [x] Add option to specify volume density in object space - [x] [D1777: Cycles: implement per shader volume step size.](https://archive.blender.org/developer/D1777) - [x] Viewport drawing and selection of volume bounds - [x] Wireframe bounds display of tree nodes (at intermediate or leaf levels) - [x] Points display type, that shows one point per coarse/fine node - [x] Selection support (based on wireframe bounds?) - [x] User interface - [x] Open file browser immediately from Add menu - [x] VDB / volume file type in the file browser - [x] Drag & drop VDB files into 3D viewport - [x] Finalize properties editor UI layout - [x] Python API - [x] Grids - [x] Transforms - [x] File loading - [x] Error reporting - [x] On-demand loading - [x] Global cache - [x] Dependency graph copy-on-write integration - [x] Refactor mesh runtime storage to be reusable by other objects types - [x] Automatic instancing for objects without modifiers, like meshes - [x] Fix runtime backup memory leak - [x] Volume frame sequences - [x] Settings to use single volume or sequence, start, length, offset - [x] Dependency graph integration - [x] Auto detection of sequences when loading file **Viewport** Time estimate: `?` - [x] Viewport selection by rendering fine boxes when drawing for selection (current volumes can't be selected except through the outliner or the origin point if visible) - [ ] Workbench: additional viewport display options - [x] Option to use lower resolution volume for viewport display **Rendering** Time estimate: `?` - [ ] Option to pick byte/half/float precision for 3D texture in Cycles and Eevee - [ ] Eevee/workbench - [ ] Share textures in global volume cache - [ ] Preserve batch cache through display setting changes - [ ] Sparse grid rendering using NanoVDB - [ ] Cycles - [x] Optimize mesh bounds creation by using OpenVDB tree - [ ] Sparse grid rendering using NanoVDB ([D8794](https://archive.blender.org/developer/D8794)) - [ ] Share 3D images like global volume cache - [ ] Auto complete grid names in shader nodes **Modifiers** Time estimate: `?` - [x] Mesh to Volume modifier - [x] Points to Volume modifier (from PointCloud or Mesh) _as a node_ - [x] Volume to Mesh modifier - [x] Displacement modifier ([D9075](https://archive.blender.org/developer/D9075)) - [ ] Texture modifier with blending modes (add, multiply) - [ ] Filter modifier (dilate, erode, blur, sharpen, ...) - [ ] Fluid Simulation modifier, replacing the current modifier on meshes for gasses (not liquids) **Other** - [x] Mantaflow: output OpenVDB files with multiple grids and standard grid names - [ ] VDB tree/voxels API using `pyopenvdb` - [ ] File packing - [ ] File saving - [x] Python API - [ ] Operator in the UI (unclear where still) - [ ] Grid metadata: show in properties editor - [ ] In the spreadsheet - [ ] Support other applications overwriting OpenVDB files open in Blender (#75901) - [ ] Volume edit mode and file saving - [ ] OpenVDB level sets, perspective transform - [ ] Cluster support (multiple grids with the same name and different transform) (#86313) - [ ] VDB files with modifiers are reloaded whenever parameters are changed, revisit this (memory vs. performance) --- **Relevant links**: * [OpenVDB Official Site ](https://www.openvdb.org/) * [New Object Types ](https://wiki.blender.org/wiki/Source/Nodes/Object_Types) design document * [Code Documentation ](https://wiki.blender.org/wiki/Source/Objects/Volume)

Changed status from 'Needs Triage' to: 'Confirmed'

Added subscriber: @brecht

Added subscriber: @JacquesLucke

Added subscriber: @Scaredyfish

Added subscriber: @sebbas

Development is happening in the new-object-types branch.

Development is happening in the [new-object-types ](https://developer.blender.org/diffusion/B/history/new-object-types/) branch.

Added subscriber: @Stefan_Werner

This was high on my to-do list, great to see that you've started work on this! Let me know if there's anything I can help you with.

Added subscriber: @garyo

This is an important feature for me as well; I'm happy to help if there's anything I can do.

@Stefan_Werner, I don't have any own code for the Cycles rendering side, which I guess you guys have (and there is also the summer of code project). So integrating that with this new volume object would help.

Beyond that I'm still iterating on the basics, it will be easier to make a concrete list of remaining tasks and distribute work in a week or two from now.

@Stefan_Werner, I don't have any own code for the Cycles rendering side, which I guess you guys have (and there is also the summer of code project). So integrating that with this new volume object would help. Beyond that I'm still iterating on the basics, it will be easier to make a concrete list of remaining tasks and distribute work in a week or two from now.

Added subscriber: @Dogway

Added subscriber: @zebus3dream

Added subscriber: @AditiaA.Pratama

Added subscriber: @Pipeliner

Added subscriber: @sergeneren

There's now basic Cycles, Eevee and workbench rendering. Still many limitations, see TODO comments in the branch for the details.
8b64765
7c144ac

Next week for me will probably be volume sequence support, and tightening up the code, in particular dependency graph integration.

There's now basic Cycles, Eevee and workbench rendering. Still many limitations, see TODO comments in the branch for the details. 8b64765 7c144ac ![openvdb_workbench_eevee_cycles.png](https://archive.blender.org/developer/F8314236/openvdb_workbench_eevee_cycles.png) Next week for me will probably be volume sequence support, and tightening up the code, in particular dependency graph integration.

For anyone who wants to help out, the tasks listed under User Interface, Workbench, Viewporting drawing, Eevee and Cycles are a good starting point. They are pretty self-contained and not likely to conflict with other changes I plan to work on.

Added subscriber: @PratyakshGaur

Added subscriber: @Peine_Perdue

Added subscriber: @RC12

Added this week:

Frame sequences for importing animations.
Global volume cache to let multiple datablocks automatically share the same grid memory.
Simpler UX for importing OpenVDB files, though Add menu and drag & drop.

Next week I plan to make the rendering and viewport drawing more complete.

Added this week: * Frame sequences for importing animations. * Global volume cache to let multiple datablocks automatically share the same grid memory. * Simpler UX for importing OpenVDB files, though Add menu and drag & drop. Next week I plan to make the rendering and viewport drawing more complete.

Added subscriber: @SteffenD

Added subscriber: @Eary

Hello, I am not a programmer, I am just a user (just trying out new things), and I discovered that the search function in the Shader Editor's Shift A menu does not work, any reason for that?

@Eary, are you saying the search function is broken specifically in a build of the new-object-types branch? I can see it greyed out when there is no material, but once adding one it works for me, same as other object types.

In #73201#867641, @brecht wrote:
@Eary, are you saying the search function is broken specifically in a build of the new-object-types branch? I can see it greyed out when there is no material, but once adding one it works for me, same as other object types.

Wait... It's fixed in the latest daily build, so never mind.

> In #73201#867641, @brecht wrote: > @Eary, are you saying the search function is broken specifically in a build of the new-object-types branch? I can see it greyed out when there is no material, but once adding one it works for me, same as other object types. Wait... It's fixed in the latest daily build, so never mind.

Added subscriber: @arc4g-1

Removed subscriber: @arc4g-1

Added subscriber: @arc4g-1

Added subscriber: @bowserlm

Downloaded the build from GraphicAll and imported a VDB and everything works in the viewport with Eevee, but when I try to render a frame with Eevee I don't get the expected result. There is no volume.

@bowserlm, that should be fixed now in f0a7a06815.

iss.vdb is too heavy to load on my GPU as a dense texture, but we can preview it in the viewport with wireframes now. Each box in the Fine display is 8x8x8 voxels.

Coarse	Fine

Velocity grid display:

`iss.vdb` is too heavy to load on my GPU as a dense texture, but we can preview it in the viewport with wireframes now. Each box in the Fine display is 8x8x8 voxels. |Coarse|Fine| | -- | -- | |![iss_coarse.png](https://archive.blender.org/developer/F8343441/iss_coarse.png)|![iss_fine.png](https://archive.blender.org/developer/F8343438/iss_fine.png)| Velocity grid display: ![smoke_velocity.png](https://archive.blender.org/developer/F8343443/smoke_velocity.png)

Added subscriber: @pixeltrain3d

Added subscriber: @BeckersC

Downloaded the latest build -- d58e80b4c6cb -- still no render result in Eevee.

Actually now no render result in Cycles as well.

***Actually looks like I am getting a render result now from Cycles and Eevee. Not sure what changed.

Downloaded the latest build -- d58e80b4c6cb -- still no render result in Eevee. Actually now no render result in Cycles as well. ***Actually looks like I am getting a render result now from Cycles and Eevee. Not sure what changed.

Added subscriber: @marks-4

Added subscriber: @theHamsta

Added subscriber: @semimetallic

Added subscriber: @Ulrich-Buch

While I assume such things to be sth. like the most low-priority of things to consider with this project, I'd still like to know in how far the new volume-object type could serve as groundwork for future support of pointclouds via OSL as per chapter 7.9 (page 72) in https://github.com/imageworks/OpenShadingLanguage/blob/master/src/doc/osl-languagespec.pdf?

Oh and sorry in advance in case this is the wrong place to ask this. :-)

While I assume such things to be sth. like the most low-priority of things to consider with this project, I'd still like to know in how far the new volume-object type could serve as groundwork for future support of pointclouds via OSL as per chapter 7.9 (page 72) in https://github.com/imageworks/OpenShadingLanguage/blob/master/src/doc/osl-languagespec.pdf? Oh and sorry in advance in case this is the wrong place to ask this. :-)

Added subscriber: @elbox01

Point-cloud sampling in OSL would share no code with the volume object, so basically unrelated. The current pointcloud texture converts point clouds to a volume, but really that's too inefficient.

Added subscriber: @nicelife

Added subscriber: @DarkKnight

Importing and rendering or shading vdb work fine but not with sequence. That only works in the viewport but the render is empty.

Still such a great addition to blender. Thanks Brecht for the work on it.

Importing and rendering or shading vdb work fine but not with sequence. That only works in the viewport but the render is empty. Still such a great addition to blender. Thanks Brecht for the work on it.

We're reviewing an in-house patch right now that's per-object (not per-shader) step size as a user parameter, not determined automatically at the moment. Rationale for per-object is that we tend to reuse the same shader for multiple VDB objects, which may have different resolutions and densities.

We might also have a patch for eulerian motion blur soon.

We have some in-house code for CPU-only sparse grids using OpenVDB directly. It's not necessarily pretty and it comes with performance penalties, not sure how useful this will be for the general audience.

We're reviewing an in-house patch right now that's per-object (not per-shader) step size as a user parameter, not determined automatically at the moment. Rationale for per-object is that we tend to reuse the same shader for multiple VDB objects, which may have different resolutions and densities. We might also have a patch for eulerian motion blur soon. We have some in-house code for CPU-only sparse grids using OpenVDB directly. It's not necessarily pretty and it comes with performance penalties, not sure how useful this will be for the general audience.

I agree per-object step size makes more sense, I was thinking about changing it to that. Probably also change it from step rate to step size, but still with a way to fill it in automatically.

We wouldn't use OpenVDB directly, since we want it to work on the GPU too, and the OpenVDB implementation in Interpolation.h has poor performance. I'm hoping we can do sparse volume rendering in Cycles for 2.83 since it would be really nice to render complex volumes, but probably I won't have time for it.

I agree per-object step size makes more sense, I was thinking about changing it to that. Probably also change it from step rate to step size, but still with a way to fill it in automatically. We wouldn't use OpenVDB directly, since we want it to work on the GPU too, and the OpenVDB implementation in `Interpolation.h` has poor performance. I'm hoping we can do sparse volume rendering in Cycles for 2.83 since it would be really nice to render complex volumes, but probably I won't have time for it.

Added subscriber: @shanberg

This issue was referenced by blender/cycles@6df79da8d7

This issue was referenced by blender/cycles@6df79da8d76610724b4c951b8eef5ffdfd234093

This issue was referenced by 7537cad576

This issue was referenced by 7537cad5761e4778da7aed02410c5811114c24e5

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This issue was referenced by fd53b72871

This issue was referenced by fd53b72871e045dfebfb9ddbe2b3c491491aa913

This issue was referenced by blender/cycles@85e8900ecb

This issue was referenced by blender/cycles@85e8900ecbd1c91c8e1f1a432c029eb80b9b6f00

This issue was referenced by 006025ead0

This issue was referenced by 006025ead0b89de671363816cd0e962f10d21c50

This issue was referenced by blender/cycles@f8b4d5c2fd

This issue was referenced by blender/cycles@f8b4d5c2fddeef7d697ae07a91d6b1ac8b730c54

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Added subscriber: @lemenicier_julien

Added subscriber: @DirSurya

Added subscriber: @shafan95

Added subscriber: @FilipMond

Any plans to access voxel data for particle system? Like to control density of VDB animation. Thank you for more info.

One of my goal was to meshing volumes (that could be done with particles generated from density with Metaballs assistance in 2.79 https://blender.stackexchange.com/questions/181773/meshing-a-smoke-simulation/182438#182438 ), but since this way is completely buggy (due the lag of particle refresh and reassigning the Voxel Data issue) it makes voxel animation impossible in 2.79 and inaccessible in 2.83 for now, right?

@FilipMond this will become possible with D4960, there is no Blender volume object involved in that.

@FilipMond this will become possible with [D4960](https://archive.blender.org/developer/D4960), there is no Blender volume object involved in that.

Removed subscriber: @nicelife

This issue was referenced by 5845c06a63

This issue was referenced by 5845c06a63a6b96f038f5a46d538b0f9737102e9

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Removed subscriber: @FilipMond

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Added subscriber: @Moamen123

For some reason this new update D9141 was not posted in here, and the volume to mesh modifier checkbox is still not checked, I was not aware of its existence until somebody told me about this today. I was like, no way, I subscribed to this post, how come I am knowing this later than you, lol.

For some reason this new update [D9141](https://archive.blender.org/developer/D9141) was not posted in here, and the volume to mesh modifier checkbox is still not checked, I was not aware of its existence until somebody told me about this today. I was like, no way, I subscribed to this post, how come I am knowing this later than you, lol.

Added subscriber: @VDC

Added subscriber: @Garek

Added subscriber: @skyscapeparadise

Added subscriber: @mkaic

Added subscriber: @Iago-Diogo-de-Vasconcelos-Mota

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New volume object type #73201