[Bf-committers] Multiview branch feedback

[Adriano Oliveira]

Hi Dalai,

I would like to contribute with some feedbacks to your branch from a user’s
point of view.

First of all, congratulations for the initiative and for the outcome so
far. It is a remarkable achievement, no doubt.



*What I like the most:*

-          Now it is possible to render Left and Right views from two
cameras in the same scene!

-          These two views are treated as layers or meta layers and can be
saved as channels in EXR 2.0!

-          It is possible to preview the two views as composites
(anaglyphs, side by side…) in 3d viewport, what is great for animators.



In my humble opinion, the problems are related to the fact that the very
implementations that allow stereo preview in 3d viewport are leading to
lack of control in Image Editor and Composite. To be more specific:



*What I am not sure of and proposals:*

-          The same approach that allows previewing stereoscopy in 3d
viewport is not as useful in Image Editor (render outcome) and Composite. I
think it is better that Image Editor only shows stereo images as long as
they have been composed in Composite as such.

-          For that reason, I would remove the “3-D” option in “Select
View”. Better: In Image Editor I would remove this new “Select View”, for
it leads to confusion when dealing with Composite outputs. Even though it
may seams repetitive, it is more correct and informative to add the views
ids in the old “Select Pass”, by adding suffixes: Composite.Left;
Composite.Right; Z.Left; Z.Right… These suffixes should be added whenever
the user activates L or R views in Render Views.

-          In consequence, stereo automated previews shoud not be a UI or
Blender Window general option in Preferences, but an option only related to
a single 3d Viewport, in the very Viewport.

-          In Composite, Render Layers nodes are lacking a switch for
choosing Left or Right, like Image nodes already have. Both should offer
Left and Right switches, and…

-          Render Layers and Image nodes should NOT offer a “3-D”
switchfor it is not useful in Composite and leads to confusion. 3-D is
not a
channel within Render Layer or Image, it’s just a fast composition option
of two layers, based on generic parameters.

-          It is more logical to get stereo outcome composing Left and
Right in a new “Stereo Node”, that would offer: 02 inputs (channels from
toggled L / R Render Layers or Image nodes), 01 selector with presented
stereo modes (side by side, over under…); 01 input numerical parameter for
convergence correction; 01 composed stereo image output.



Very important: this Stereo Node is only for final composed output files
(PNG, TIFF) and Movies. We need to implement another new node for
“optional” re-merging the decomposed L/R views for output as channels in
Composite (for editing stereo in Sequecer, for instance) or as
channels/layers in EXR 2.0 files.

This logic of decomposing layers to better work with them, and then merging
them together later with a new “Merge Channel” or “Merge Pass” node is
similar to what Nuke already does. This only would be (stereo aside) a
great implementation in Blender Composite, and must in EXR 2.0 logic.

I hope to help.

Adriano A. Oliveira