Subset Pixels and Backburner Rendering.

[Crazy Homeless Guy]

This thread is primarily a question to Justin, regarding the thread link below, but maybe someone else has answers also....

http://www.cgarchitect.com/vb/36756-polygonal-lasso-region-render.html#post257847

 

____

 

The first image represents what I get on my local machine if I select the "Subset Pixels (of selected objects)" in the Rendered Frame Window dialog box, or Subset Pixel Rendering in the Renderer roll out. They are the same thing.

 

I have all of the blue boxes selected. The scene renders fine, and you can see that the alpha is correct. In theory this is usable, though I have yet to use it in production because I think there might be issues with the blue pixels blending to black, rather than whatever is in there neighbor is. But that is just my concern, and not actually tested.

 

The second image is rendering via Backburner, using the same process. As you can see, it rendered the entire image, instead of the subset. Also, it placed a white fringe line around my subset, and the fringing is somewhat visible in the alpha channel.

 

Maybe you can not render on Backburner this way, but mentioned that you have fixed animations using this method in the past, so I am assuming you network rendered the correction. Am I wrong on this assumption?

 

The way I usually handle this when network rendering is to use the Render Subset of Scene/Masking shader. Using this method it works great, but setting up this method can be a pain. I typically render with lots od 3d bushes, trees, and cars. Adding 4000 bushes to the subset shader can sometimes take an hour. So it becomes a real pain, especially if something is missed or a mistake is made in the process.

 

Actually, the pain would be fixed if you could add groups to the subset, but MR/Max does not allow you to do that.

 

I could save myself a lot of time if I were able to tell it to render the subset of my selected objects, and have that operate through Backburner. It only takes a minute to select all of those objects, compared to the hour for adding them to the subset shader.

 

Anyway, thoughts or comments.....

Edited August 23, 2009 by Crazy Homeless Guy

[Justin Hunt]

The two "Sub-set of Scenes" are different , ie the on in the render dialogue and the Shader.

 

Use the render "Subset Pixel Rendering" dialogue to isolate objects whilst tweaking their shaders or lighting.

Use the Shader "Subset of scene/Masking (mi)" for creating masks and with Backburner.

 

I am sure you know the steps but this is the methode I use:

 

In the render dialogue ->camera effects -> lense, load "Render Subset of scene/Masking (mi)"

Drag it to the material editoe as an instant

In you scene select everything that you want to render (Yes its a pain that Groups are not loaded as a whole so OPEN the groups)

Click "Add" in the material editor

Click on the "Select by Name" button and eveything that is selected in the scene should already be highlighted.

Click Pick

everything, including the open groups will be listed

Submit to backburner as usual, just be sure to be saving the frames to a format that supports Alpha chanels.

 

I have found that if you keep the lighting , FG Photons etc exactly the same there will be no boarder, or at least none that I have noticed.

 

Things to Note

 

RPC's render with a large rectangle as the alpha, as long as the lighting is the same in both renders this is OK, but if there are changes then you will see the rectange "halo"

[Crazy Homeless Guy]

The two "Sub-set of Scenes" are different , ie the on in the render dialogue and the Shader.

 

Use the render "Subset Pixel Rendering" dialogue to isolate objects whilst tweaking their shaders or lighting.

Use the Shader "Subset of scene/Masking (mi)" for creating masks and with Backburner.

 

I am sure you know the steps but this is the methode I use:

 

In the render dialogue ->camera effects -> lense, load "Render Subset of scene/Masking (mi)"

Drag it to the material editoe as an instant

In you scene select everything that you want to render (Yes its a pain that Groups are not loaded as a whole so OPEN the groups)

Click "Add" in the material editor

Click on the "Select by Name" button and eveything that is selected in the scene should already be highlighted.

Click Pick

everything, including the open groups will be listed

Submit to backburner as usual, just be sure to be saving the frames to a format that supports Alpha chanels.

 

I have found that if you keep the lighting , FG Photons etc exactly the same there will be no boarder, or at least none that I have noticed.

 

Things to Note

 

RPC's render with a large rectangle as the alpha, as long as the lighting is the same in both renders this is OK, but if there are changes then you will see the rectange "halo"

 

That is what I am doing. I need to subset the entire landscape in the current scene we are working on. I am scheduled to receive final building geometry by noon tomorrow, but am sending off landscape passes tonight to make the process of meeting the deadline smoother.

 

Unfortunately the landscape pass contains 9,500 objects. It takes awhile for the subset shader to load these. I was a little presumptuous in my hour estimation, it actually only took 35 minutes. But it is still time consuming, and enough to drive you batty if you happen to make a mistake along the way.

 

I mis-undertood your previous post, and thought you had a way to render a subset of selected objects on the network. Oh well. A man can hope.

 

Actually, I think there are some Scriptspot scripts that deal with this kind of thing. Maybe I can find something there.

 

Along with groups, it would be helpful to be able to render Xref's scenes as subsets. At least it would be helpful in my workflow.

 

Thanks for the response.

[Justin Hunt]

You can add everything selected at one time by using the "Select by Name" button

 

I have added 1000's of objects in one got in seconds. This one took 20 seconds or so to add 2601 teapots

 

jhv

[Camby1298]

You can add everything selected at one time by using the "Select by Name" button

 

I have added 1000's of objects in one got in seconds. This one took 20 seconds or so to add 2601 teapots

 

jhv

 

Thats interesting, when I try adding thousands of objects (say for a landscape/tree/bush pass) I use the same method. But I find that I try to time it to select every object within the shader before I go to lunch; usually the selection will take 15-45 mins (depending on number of objects). Im curious how youre getting thousands of objects selected within seconds????

[Justin Hunt]

Logical naming conventions and layers makes selecting much easier. Complex model structures can add a heap of time when selecting and even basic manipulation. Named selection sets can also make things easier.

 

Cant say I do anything special though

 

jhv

[Crazy Homeless Guy]

I've been doing a bit of testing. The proxy objects seem to be what is really slowing it down. No proxies, quick add. Lots of proxies, painfully slow add. Lots of proxies, meaning 9000+ in this case.

 

Now, I need to figure out if it is actually the fact that they are proxies that is slowing it down. Meaning, Max is loading information in, adding that proxy, unloading it, and then repeat. Even though the shader only actually needs the name.

 

Or, .....is the RAM consumption for the process climbing, causing Max to slow down as it gets higher, and taps into the paging file.

 

Or, ....a combination of both.

 

Which is what I think it is. I tried adding 30,000 teapots, and it was taking long enough that I killed it before it finished.

[Justin Hunt]

interesting, I try some testing this side too

 

jhv

[JoeHarford]

Just a quick thanks to Justin for the useful info at the start of this thread. Cheers.

[Justin Hunt]

Glad to help

 

jhv

[iduna79]

Thanks Justin Hunt! Great support that saved me