Corona Multi-Pass

[BigAl3D]

I'm running Beta 1 rc3 on Mac.

Since there have been several new builds since the last threads I found about Multi-Pass and Object Buffers, I figured I'd start a fresh one here. I have an animation already rendered, then my boss wanted to change the background color. I didn't render in separate passes, so all I need to do is assign an Object Buffer to the Background object so everything in front of it is masked. This is ease with the native engines, but all I get is a solid black mask out of Corona.

I found the Buffer settings in the Corona Compositing tag and set it to 1. The new issues, where do I enable the Multi-Pass in the render settings? I can't find it. Please help. This is the last piece for my project. Thanks.

[TomG]

Corona has its own Multipass dialog, open it from the Corona main menu, Multi-Pass. You can then enable (or disable) all passes at once with the top checkbox, or each pass individually as needed. You may find the "Render only masks (disable shading)" in the General settings tab under the Render Settings dialog to be of use too!

[BigAl3D]

Mind. Blown.

Wow, there's a lot of stuff in there. I still haven't been able to figure it out. Can you give me a quick overview or a link to how to use this system? This is the first time I've seen it.

Thanks for your help.

[BigAl3D]

OK I managed to render out the proper mask. It's almost perfect, BUT as you can see in the posted image, it's not perfectly blending with the car. The car was rendered with a white background and motion blur. I made a mask for the car, but the blur isn't matching perfectly. I also tried using the Standard and Physical renderers for the mask, but also did not match.

Any ideas how I can fix this?

Edit: I am able to reduce the halo effect quite a bit in AE using some curves, so if I have to, I can get away with that.

[TomG]

The Multi-Pass help documentation is at https://help.c4d.corona-renderer.com/support/solutions/articles/12000023596-what-multi-pass-channels-are-available- (along with lots more C4D help on those pages!)

[TomG]

On the mask, I think the issue is that the original pixels were already blended with the white (the background) since they were blurred and had to "spill over" into the background.

Doesn't help avoid re-rendering here, but you can use a Velocity mask to add blur in post, which will then do that blending with the background in post rather than at render time. The 3ds Max tutorial for Velocity would cover how all that works (https://www.youtube.com/watch?v=6Hk2jhbQTuI) other than it's name is different in Max :)

In this case, since the mixing of colors is already done at render time, I think your curves are likely the only solution unfortunately. Someone will correct me if they can think of a better workflow! (I would try getting a solid mask for the car, so I can leave that untouched, and then adjust the remaining exposed "blurred bits" with curves and mixing modes while leaving the blurred car itself unaffected)

[lenogre]

Is the BloomGlare pass working ? It's always black, black, black…
I don't understand.

[TomG]

Bloom Glare pass is not working at the moment.

[lenogre]

OK

[BigAl3D]

I'm reviving my old post here as I just tried to get a Geometry Vector pass and all I get is a black channel. I followed the help files, disabled all motion blur, tried Camera vs. World. Just black. Is this feature fully implemented yet for Cinema 4D? I also tried it on Windows 10, C4D R20. Same results. I would post an image, but it would just be a black square. ;-)

Full-speed non-debug version
Build timestamp: Oct 11 2018 10:27:39
Version: B2 rc 2 (core 3 (DailyBuild Oct 10 2018))
Cinema version: CINEMA 4D Studio R20.028

[BigAl3D]

No updates on multi-pass and velocity vectors?

[BigAl3D]

The reason I'm trying this method is for a workaround to the Mograph-motion blur issues the Corona devs are working on. Figured if this pass works, then I can try Real Time Motion Blur plugin in AE.

I just tried it with a Corona camera, saving the output to file and enabling Multi-pass output in the Save dialog. Still nothing.

[TomG]

Can you clarify what you mean by "nothing" just so we know for sure what you are describing? Is it that the render element is there, but it's all black? Or is it that it is missing? If it is there, have you inspected it in the VFB (right click with the mouse) to see what the values are, since they are usually out of range for display (they don't always map to colors) - are the values showing as 0,0,0 or do they have some values and data in there? Or by nothing do you mean there is stuff in that pass, but no motion blur from RSMB?

Also don't forget that RSMB (which we can't test as it's a paid plugin) may require a different format - there are two parts to that, world or camera, and then there is sometimes an offset needed (the exact settings for RSMB escape my memory at the moment, you can maybe find it with a forum search as it has come up before).

[BigAl3D]

Thanks for the reply. I'm attaching my test file. A simple cube moving across the screen and spinning. I first tried this test on a scene with Mograph Instances, but I figured let's see if it works on a simple scene, but I must be dumb. Well, maybe just a little.

The render element is generated and yes, nothing. All 0,0,0. In the VFP and Photoshop. Just black. Alpha and other passes seem to work. In the example video Corona posted (using Max), there were only a couple of settings to set up and the file generated is bright colors. That's what I was expecting to see.

I haven't used RSMB either, but you can use it in trial mode with watermark. I'm running on a Mac by the way. I will test on Win 10 box to confirm.

Do you think RSMB will work with Corona's Velocity pass based on this info?:

**********
What is the motion vector format for RE:Vision Effects’ products?

Motion Vectors
We use pixel space motion and not 3D or 3D normalized coordinates. That is, each pixel value of the motion vector image should represent the motion of a pixel within one frame time, in image space.

In our coordinate system, the lower-left pixel represents the origin of the coordinate system, (0,0), with positive Y-axis pointing up. That means a motion vector value of (1.0,1.0) represents a motion of a 1.0 pixel in each of X and Y toward the top right corner of the image.

**********

[BigAl3D]

@TomG Any updates on this Velocity issue I posted about? I still can't get it work at all using Beta2 on Mac or Windows.

I just found an older thread with the same Velocity pass issue. Didn't see it before I posted to this thread.

https://forum.corona-renderer.com/index.php?topic=19507.0