3D Keyer in Edit page - Multiple strokes do not work.

Hi, there is a bug (I believe) with the 3D Keyer when used in the Edit page for me. I believe it is a bug as the 3D Keyer works perfectly in the Fusion page.

The issue is that after I have done the following:
- put the video clip with the green screen onto the timeline,
- dropped the 3D Keyer effect onto the clip,
- selected the "Open FX Overlay" option for the viewer, and
- used the eyedropper PICK tool from the 3D Keyer Effects menu to make the first selection of the green screen...
Then when I try to add a second stroke to refine the key by selecting the eyedropper ADD tool and dragging a second stroke, the viewer windows shows that many parts of the image, including half of the subject who has no green colour on her, get selected.

I have tried all Output settings (Final Composition, Alpha Highlight BW, etc), but still have the same issue.

Note that when I use the 3D Keyer in the Fusion page, it works perfectly and allows me to add mulitple strokes correctly, (Both ADD and SUBTRACT).

I am using Davinci Resolve Studio 18.1.2 on my Windows 10 (22H2, OS Build 19045.2546, ie the latest Win10 build). I have an RTX3080 and i7 CPU and 48GB RAM.

Any ideas, suggestions, or how to post this as a bug to be investigated by the development team... unless I am missing something?

It is definitely a bug, at least on my system, and I have managed to get the 3D Keyer to work correctly in the EDIT page by doing this odd series of things:

(1) In the Edit page, put the timeline marker over the video clip with the green screen - I have multiple clips on the timeline. I have already confirmed that the 3D Keyer effect placed on this clip does not work correctly (see previous post) and now I delete the effect from the clip,

(2) Go into the FUSION Page,

(3) Add the 3D Keyer node between the two nodes, then select the 3D Keyer for display in window 2. Now select the green screen using the eyedropper tools and make multiple strokes, just to test that it is working, which it does,

(4) Delete the 3D Keyer node.

(5) Return to the EDIT page and right-click the clip and select "Reset Fusion Composition"

(6) Add the 3D Keyer effect back onto the clip...

AND IT WORKS PERFECTLY!

HOWEVER this is still an issue (a bug) as I cannot simply drag the 3D Keyer to the other clips on the timeline as they will not work correctly until I go take each clip into the Fusion page and perform the same steps above.

Interestingly, if I delete the 3D Keyer effect from a clip in the EDIT page, and then re-apply the 3D Keyer effect to the same clip, then it works perfectly, ie I can use multiple strokes to select the green screen correctly. However if I drag another clip on the timeline and add the 3D Keyer effect to it, I have the same issue as originally described.

I even tried deleting the effect and then closing Davinci down completely. When I restart Davinci and add the 3D Keyer effect to the same clip, it works perfectly and I can add as many strokes as I like.

Any ideas? How do I post this information to the Software development team as I believe this information will be useful for them to be able to address the bug?

FYI, I have sent this to Blackmagic Design Support.

I will post the results here and keep you posted.

BUMP

Anyone here have any ideas or things I could do to address or fix this issue?

I haven't heard anything back from Blackmagic Design Support as yet, however I imagine that they are very busy the version 18.1.3 release.

FURTHER UPDATE:
I have installed v18.1.3 but still have the same issue, however my solution to address it no longer works.

After much effort I have found one method that "sometimes" works for me. It is as follows:

(1) In the Edit page put the clip with the green screen on the timeline, place a white slide underneath - this will be the background after the green screen is keyed out... and place the timeline cursor over the clip,

(2) Go into the Fusion Page,

(3) Add the 3D Keyer node between the two nodes, then select the 3D Keyer for display in window 2. Now select the green screen using the eyedropper tools and make multiple strokes, just to test that it is working, which it does, and select "Final Composite" at the bottom,

(4) Go back to the Edit Page. The green screen will be keyed out correctly showing the background, however the background will be a strange yellow colour and look completely wrong. Don't worry about this,

(5) Drag the 3D Keyer effect onto the video clip. Then right-click the clip and select "Reset Fusion Composition"

(6) Now the 3D Keyer effect will work correctly, ie I can use multiple strokes to select the green screen correctly.

Other notes. If I change the Playback from Full to half or quarter, then the 3D Keyer never will work for me. I always keep it at Full.

What's going on?! This is one of the fundamental OpenFX that I imagine many people use to key out green screens.

HELP?! Please.

Honestly, I just tried this with 18.1.3 (Studio) and I can't get it to work, either. After the initial selection of the green screen color all subsequent add or subtract strokes pick up the mask colours of 255,255,255 (white) or 0,0,0 (black) rather than the color of the source video. I'm not sure I've tried the 3D Keyer OFX in recent releases of Resolve but this is definitely broken (does not agree with the behaviour outlined in the reference manual).

Thanks for your reply. It is comforting to know that I am not alone with this issue.

I'm surprised though that more people are not calling this bug out as the 3D Keyer, I imagine, is widely used.

Thanks for your reply. It is comforting to know that I am not alone with this issue.

I'm surprised though that more people are not calling this bug out as the 3D Keyer, I imagine, is widely used.

I saw the problem with 18.1.2 on edit page. Because Resolve gets buggy the more you use it, I had thought I either had to restart Resolve or computer, and it would work fine. Partially because like you said there's been no posts about it. I used a 3rd party keyer instead.

I still have to think this surely can't affect everyone, or there would be posts about it, 18.1.2 has been around since December

I still have to think this surely can't affect everyone, or there would be posts about it, 18.1.2 has been around since December

Agreed. However maybe everyone thinks like us and that the issue is not widespread. It's really odd. I hope that Blackmagic Design support gets back to me soon.

SOLUTION - or rather, "Effective workaround".

BlackMagic Design USA (not Australia) support got back to me... and they are brilliant! Thanks Dmitry!

In short, this is a known bug which they will work on rectifying.

In the mean time simply follow their instructions which is simply to click on the Color Page and then back to the Edit page; the 3D Keyer effect then works correctly. This works perfectly for me.

Message from Blackmagic Design support:

"Go to the Color page just before using the controls of the effect on the Edit page. You do not need to do anything on the Color page. Go there and back to the Edit page."
"That makes everything behave as expected, even without disabling the Auto B/W Highlight option."