09 juin

Blender Stereoscopic 3D

Rédigé par JG Loquet | 5 commentaires |
The upcoming 2.75 release of the Blender 3D animation open source creation software includes a set of new "Multiview" features for working on 3D stereoscopic projects with better ease and performance.

It can render stereoscopic images in the viewport as anaglyphs or - more usefully to me - using active steroscopic displays.

I decided to test it on my laptop (Corei7 8GB RAM nVIDIA GeForce 555M 3GB Win64) with an active nVIDIA 3D VISION display, using the blender-2.75-testbuild1-windows64 version.

Enabling stereoscopic features is pretty straightforward (just check the Views box in the scene properties). By default it uses Anaglyph display, to use my active display I enabled the "Time sequential" display mode in the "Set stereo 3D" item of Blender's "Windows" menu.

Blender multiview anaglyph display

It needs to be in full screen mode (Alt-F11) to work, which is handy since it allows to switch stereoscopy on and off with one shortcut.

For the occasionnal stereoscopic video maker that I am, Blender provides a pretty good set of tools and allows to quickly set and visualize stereoscopic parameters such as convergeance and interocular distances (stereoscopic panel of the Camera properties)

Blender stereoscopic camera parameters

I have tested it on my setup with several of my scenes (some counting over 4 milion polygons) display is still relatively fluid and I wasn't able to make it crash with the kind of scenes I use in production.

I tested it in edit mode, trying to model in stereo using the Lock Camera to View switch : I was a bit disappointed since I expected that the stereo display would help see/select vertices more easily, but with the mouse pointer staying 2D that wasn't the case, instead it made things less handy, so staying out of stereo mode for editing is probably a better choice. Same applies to sculpting and painting modes :/

(Maybe having a 3D pointer would be an usage for the legendary 2 mice setup ? :P probably tough to get used to though ..)

However, looking at your models (in object mode) in stereo 3D really helps getting a more precise idea of the model's shape and spot small topology problems.

Many good surprises :
  • rendered images in the image editor are displayed in stereo (using the set display mode, in my case "Time sequencial")
  • the new "Views format" settings in the output allows to automatically save stereoscopic images in the side by side (or anaglyph) format
  • you can use a stereoscopic movie / image sequence as a background image in the 3D viewport, thus allowing CGI / live action integration previsualisation in real time
  • the viewer node of the compositor also works in stereo, and a new "Swich view" node allows working on each L/R channel separately
  • the video sequence editor image preview window also works in stereo, thus offering a complete stereoscopic video production and post-production pipeline right within Blender !

Blender stereoscopic video editor

Blender stereoscopic live action background plate

I can think of one small improvement that would save time in post-production (for pop-out texts and that kind of simple stereo effects) at a probably low development cost : being able to set a different x image offset for each L/R channel of a sequencer strip.

Thanks to Dalai for the comments and tips !

Well, that's about it for today, looking forward to reading your comments below.

As always kudos to the Blender devs for this awesome new feature, you guys rock !

Now off to translate all this in french (some day :P)


5 commentaires

#1  - Dalai Felinto a dit :

Hi there,
First of all, thanks for the write up. I'm glad you will be able to use Multi-View in the upcoming Blender.

I couldn't help noticing that your two suggested improvements are already (supposedly) supportted.

You can even find some images of it in the manual:

> 1. Being able to use active ("time sequencial") stereoscopic display in the VSE and in the compositor viewer node, which would allow fiddling with stereo parameters in post and check the stereo effect (pop-outs and the kind) in real time, and thus completing a full stereo pipeline.

As far as I can tell this is properly supported both in the VSE and the viewer node. Could you clarify what is not working?

> 2. Being able to set a different background image for the Left and Right Camera, as all the stereoscopic videos I worked on also used stereo live action footage background/foreground plates.

This is also supported. As long as the background image is a stereo 3d image it will display the correct eye in the viewport.

Let me know if you manage to test the above two enhancements :)

#2  - JG a dit :

@Dalai Felinto : Hi Dalai,

Thanks for your reply.



I have tried again the viewer node and this time it worked. I don't know what happened the first time and I wasn't able to make it not work again, so that's cool :)

I have also tried again the VSE, and found the "Use multiview" check in the strip's properties that I didn't notice the 1st time (that's not in the manual is it :P ?) and this works too, also cool :) but thus I found what I think is maybe a bug : the saturation and multiply properties of the strip only affect the left channel on the frame you set it (but seems to work OK on the other frames) ..


I have tried loading a stereo image (saved with Blender and that loads OK as a stereo in the VSE) as a Camera background image but couldn't manage to have it work as a stereo background :/ is there a switch somewhere ? I couldn't find this in the manual either

Anyhow, the stereo camera I've worked with doesn't save one stereo image per frame but two separate images one for the R and one for the L so maybe it would still be useful to be able to set a different image sequence for each channel as a Camera background ..

Also, I've read the manual a couple of times and fiddled with it for a while, maybe it's just me, but I can't figure out how the "Switch view" node works and what it's supposed to do :/ maybe it would be cool to explain a bit more in the manual ?

Cheers !

#3  - Dalai Felinto a dit :


The switch node is explained here:

Do you mind reporting your VSE bug on http://developer.blender.org?

Stereo pairs (e.g., images in the same folder with different suffices - Video_R.mov, Video_L.mov) are interpreted as Stereo data if you use the 'Individual Views' format (as oppose to the Stereo 3D). You can pick 'Use Multi-View' while loading the image.

(that said, the background in the viewport apparently is not working, mind reporting this as well?)

Last but not least, I agree that the manual could use an update. I finished the manual before some last minute design decisions, so VSE is not covered, as well as the nitty gritty of I/O.

Thankfully the manual has a low entry barrier than the code, so someone may even pick it up before I update it ;)

#4  - JG a dit :

@Dalai Felinto : Hi Dalai,

thanks for your reply. Here :

Switch node : OK I got it figured out thanks to your video. It's a bit confusing at first that the same node sperarates AND recombines L/R channels but once you're used to it, it is probably more efficient that way.

VSE bug : couldn't replicate it today .. very weird because I replicated it 3 times last week (maybe some bug with my graphics card or a buffer issue ??)

Background : tried loading it first in the image editor thus being able to tell Blender what kind of stereo image it was, and then in the 3D viewport as a background image : it works perfectly :)

I noticed another thing : when I "set stereo 3D" it always automatically creates a new Screen Layout (like Default.001) is that how it's supposed to work or could it be a bug ?

All in all this is absolutely rad, a complete stereoscopic 3D animation and VFX pipeline right within Blender :D !

One last suggestion for the VSE : it'd be a big plus to be able to set a different x offset for each L/R channel of a stereo strip, to fine tune stereo effects at edit time (more convenient and faster than in the compositor) ..

Now off to try and see if I can manage adding the VSE part to the manual, just my tiny bit of help :P ..

Thanks Dalai !


#5  - Jackiebonny a dit :

Merci beaucoup pour cet article, je suis sur d’avoir énormément appris

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