Rendering Out in Layers

[James Taylor]

hi all,

was just wondering if its possible to render from viz 4 in layers. I've done it once from Maya when at uni but never used it again.

A project were undertaking is getting a high poly count and our machines are beginning to struggle. Thought this might be a suitable answer for breaking the scene size down.

Any suggestions or thoughts as whether its posiible or worth trying would be most appreciated.

Thanks James.

[Chad Warner]

You can use the "render Elements" option on the render dialog, and render out shadows, refections, etc.

-Chad

[James Taylor]

I've had little play with the render elements. But i'm not sure its what i'm looking for. Rarther than rendering out the different elements of shadows, diffuse colour reflections etc. i'm looking to render the actual geometry in layers which can then be composited together using after effects or something similar to form the final image.

Thanks James.

[Jonathan Ashton]

Might be the same as Max 6.

If you organize your scene by layers then you can select all in a layer and then 'render selected'....very useful.

[Jennifer O'Connor]

Rendering just what is far away to a separate file and using that as a background later is probably what you are getting at when you say 'render in layers', and is generally a great timesaving technique. You then use the Far images as a background when you render the close-up objects, and would not need to composite it in another program.

However, if you save the Close and Far images separately and composite it in After Effects or Combustion, then if needed you can modify the Far without having to re-render the Close. A 'cover your butt' kinda thing, but there are some things to consider.

If rendering to separate Close/Far images for compositing later, be sure that you use PNG or TGA image format for the Close images, and enable the Alpha option. This way your background will show through the Close images when composted. For the Close rendering, you may also have to disable Antialiasing against the background, or you will see some strange pixilation along the composite seam. VIZ will want to blend the Close objects against the background color otherwise. (Note that if you are simply using your Far rendering as a background when you render the Close objects, then this paragraph does not apply.) You could also use a chroma-key compositing technique in AE/Combustion, rendering the Close scene with the background as a bright green or blue, and composite that way.

As far as other techniques....

For very large projects we will separate the scene into 'render blocks' of sorts, and XREF out the areas we don't need at the moment. For an exterior rendering, for instance, we may need the entire scene for the first X frames, then we can turn off buildings and trees that are behind us (provided they are not in reflections) and continue Y frames, until there is more that we can turn off, and so on. For an interior we may turn on or off XREFs from specific floors or rooms as they come into, or leave, our view.

You could also group the objects as described above, and use an On/Off Visibility track on the group. Animate the turning On/Off of groups as needed. This will speed rendering, is simpler to implement, but the objects are still in memory. If memory is an issue (you are paging out to the hard drive while rendering) then you need to look at other techniques.

To keep memory down, it will take manually controlling which parts of the scene are needed, enabling and disabling the XREFs you need, and creating network render jobs of the frame ranges needed. The render time saved is worth the effort, certainly.

Consider, also, separating your animation into segments, and doing a cross-fade between segments rather than a straight walk-through. It can be more visually interesting, but you have to ensure that viewer understands where they are when the transition is made.

Have fun!

[Mike Tutaj]

Take a look at www.rpmanager.com I have been starting to try it out. works pretty good so far.

Mike

[William Alexander]

jat10005,

Yes it's possible, basic image layering just like PS. You need to have good alpha channels to really make the masks work, obviously. Render elements can be very helpful to aid with mask creation. Sounds like mutaj's app could help the workflow.

Hey it's done everyday in the VFX pipelines, all layers are rendered out seperate and combined in comping' apps. Even using the likes of lume elements to mask complex lighting and fire type effects. The hardest part is management off all the pieces. A blueprint for the rendering of the blueprints (storyboard).

Cheers
WDA