Hi
I’m trying to render a scene containing moving objects in a room. The scene is lit using geometry light and GI light.
My objective is to render the room and objects as separate object-passes that can be comped in BM Fusion.
My first attempt, was to add a mantra node for each part, and assigned the other objects as Forced Phantoms. It worked well, but the GI light is missing.
My second attempt included only one Mantra node. I saved the file as an exr file with object id assigned. The problem is that the object id mask does not contain any motion blur. Using soft edge in Fusion helps, but it’s not good enough.
What's the best way of render object-passes for composition?
Rendering object-passes in Houdini
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- Reco
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- Enivob
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Check out the term “Extra Image Planes”. That is what Mantra calls passes.
There are some default check boxes for common passes you might want but you can also click the + icon and add a new pass. Click the Vex Variable dropdown for the complete list. I believe you can also route attributes to image planes as well.
There are some default check boxes for common passes you might want but you can also click the + icon and add a new pass. Click the Vex Variable dropdown for the complete list. I believe you can also route attributes to image planes as well.
Using Houdini Indie 20.0
Windows 11 64GB Ryzen 16 core.
nVidia 3050RTX 8BG RAM.
Windows 11 64GB Ryzen 16 core.
nVidia 3050RTX 8BG RAM.
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- Reco
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Thank you for your answer Enivob
I know about the Extra Image Plane and passes. That’s why I using the word Object-passes, just because I don’t know what to call it. Layers is maybe a better word.
The second attempt was done using and Extra image plane with Op_Id as the Vex Variable. It works in a way. I can use the id to limit a color correction to a single object only. But the mask has no motion blur, so it does not match the object in the image.
What I want to do is. Let’s say you have a helicopter flying around a building. Then I want a file of the helicopter only, a second file of the building only and a third file of the background. I know I can do this using tree Mantra nodes. (and I have done it). The first for the helicopter with the background and building as Phantom Objects. Second, building only and helicopter and background as Phantom and the last with background only and Helicopter and building as Phantom.
The problem is, the GI light doesn't work using this method.
I know about the Extra Image Plane and passes. That’s why I using the word Object-passes, just because I don’t know what to call it. Layers is maybe a better word.
The second attempt was done using and Extra image plane with Op_Id as the Vex Variable. It works in a way. I can use the id to limit a color correction to a single object only. But the mask has no motion blur, so it does not match the object in the image.
What I want to do is. Let’s say you have a helicopter flying around a building. Then I want a file of the helicopter only, a second file of the building only and a third file of the background. I know I can do this using tree Mantra nodes. (and I have done it). The first for the helicopter with the background and building as Phantom Objects. Second, building only and helicopter and background as Phantom and the last with background only and Helicopter and building as Phantom.
The problem is, the GI light doesn't work using this method.
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- matthias_k
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- Nicolas Heluani
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I feel there are a few things that I may be misunderstanding from the original post, but just in case it helps here are a couple of things to have in mind:
- When you set the extra image plane in houdini to Op_Id be sure to leave the pixel filter option blank, that is if you want to use the same pixel filter you use for your main beauty pass. this will generate an obj id for each object in the scene filtered and with motion blur as the attached image. For your situation this seems the appropiate solution.
- As for different object passes. I feel that will be a bit more complicated to create but then I will explores takes.
Edited by Nicolas Heluani - Oct. 8, 2016 11:32:18
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- Nicolas Heluani
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matthias_kAllow image motion blur tick basically says to houdini to output images without motion blur regardless if you set up your render to calculate it. I really do not understand why would this be useful but there it is. So basically when you set motion blur but uncheck that box mantra will calculate the MB but not output it…again, I don't understand the use of it but well.
Maybe a Bug, in 15.5.607 motion blur is applied in Preview Mode but not in final render.
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- matthias_k
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- Reco
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Thank you Nicolas.
1.The pixel filter was the problem. I set the pixel filter to minmax idcover, as described in an old tutorial. Keeping it blank, generated an object id with motion blur. But unfortunately I have some problem on the composition side.
2.The basic is not difficult at all. I don’t have to use Task at all, but you can go that route it you want to. Please see my examples. I can render separate pieces, but the GI light is left out, so the objects are much darker. Maybe this is due to some photon problem since only one object is visible in each render.
I’m coming from Lightwave, and in Lightwave there is an option to tick off an object as unseen by Camera. There is no interruption to the scene at all, the selected object will just not show up in the rendered image. It is still reflected in other objects. I thought Force Phantom worked in a similar way.
(Not sure how to add text to each image)
Below you can see a Houdini scene were all objects are rendered.
Then a setup were all objects are rendered using one Mantra node for each object.
Then a setup in Fusion.
And a color corrected plane (Yellow) in Fusion.
The two last images shows a setup using Object ID.
Houdini render the ball in many passes in order to generate motion blur. All those passes has it's own ID in Fusion.
That is a Fusion problem and I will check this out in the Fusion forum.
Hope you understand what I am trying to achieve.
Thank you again
Reco
1.The pixel filter was the problem. I set the pixel filter to minmax idcover, as described in an old tutorial. Keeping it blank, generated an object id with motion blur. But unfortunately I have some problem on the composition side.
2.The basic is not difficult at all. I don’t have to use Task at all, but you can go that route it you want to. Please see my examples. I can render separate pieces, but the GI light is left out, so the objects are much darker. Maybe this is due to some photon problem since only one object is visible in each render.
I’m coming from Lightwave, and in Lightwave there is an option to tick off an object as unseen by Camera. There is no interruption to the scene at all, the selected object will just not show up in the rendered image. It is still reflected in other objects. I thought Force Phantom worked in a similar way.
(Not sure how to add text to each image)
Below you can see a Houdini scene were all objects are rendered.
Then a setup were all objects are rendered using one Mantra node for each object.
Then a setup in Fusion.
And a color corrected plane (Yellow) in Fusion.
The two last images shows a setup using Object ID.
Houdini render the ball in many passes in order to generate motion blur. All those passes has it's own ID in Fusion.
That is a Fusion problem and I will check this out in the Fusion forum.
Hope you understand what I am trying to achieve.
Thank you again
Reco
Edited by Reco - Oct. 8, 2016 17:10:23
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