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I noticed something last night trying to optimise a scene for speed. Even hidden objects will slow down the sampling rate! By hidden I mean via 'object dissolve' or 'unseen by camera'. The only way to truly remove these objects from the octane rendering equation is to make them inactive in the scene editor.

All items visible IPR tells me I'm getting 18.13 ms/sec.

Items Visible 'Hiding' the objects using Object Dissolve @ 100%, now IPR says 14.96 ms/sec.
Hm...slower with invisible (100% dissolved) objects?

Items Invisible Keeping these 3 items at 100% dissolve, now I also check 'unseen by camera' and Uncheck 'cast shadow'. IPR still says 14.96 ms/sec
Effectively it seems the scene renders slower if these items are set to 'invisible'!

I want it faster not slower, that's the whole point of hiding objects when I don't need them. So this time I toggled the active state in the scene editor, and bingo- 63.92 ms/sec. Three and a half times faster which is what I'd expect since 3/4 of the items in my scene aren't being rendered.

Items Inactive So..

All of my items visible rendering at 18.13ms/sec
100% invisible items rendering at 14.96 ms/sec
100% inactive items rendering at 63.92 ms/sec

This means that in my project scenes whenever I had objects 'hidden' but still 'active' in the scene editor, I thought this might speed things up but it's actually doing the opposite and slows down the renders.

While this might seem obvious to some I've also noticed something else. I had a bunch of luminous polygons throughout my scene and even when these lumigons we not in frame and power set to zero, and set to invisible, they still slowed down my renders

Great tip. Thanx bro.

Thanks!

Good find.

Wish the renderer could 'mark' those items, discount them from the render tree and auto-magically speed up.

UnCommonGrafx wrote:Good find.

Wish the renderer could 'mark' those items, discount them from the render tree and auto-magically speed up.

I'm looking into some scipts/plugins that can help automate the task of making lights/lumigons/objects inactive in the scene editor when they're not needed. That way rather than adjusting 'dissolve' or 'visible to camera' flags, it completely disables it from Octane. For me typical usage would be "if Cam X is selected, hide Items/Lights ABC & D. Will check back when I've found something workable. So far LayersMC looks like a promising way to save and enable/disable groups of items in the scene editor:

https://www.youtube.com/watch?v=c8fdaCgzXbk

Maybe it's me, but I would always use the scene editor to remove things from rendering. Why would you use 'dissolve' or 'invisible to camera'? anyway.

gordonrobb wrote:Maybe it's me, but I would always use the scene editor to remove things from rendering. Why would you use 'dissolve' or 'invisible to camera'? anyway.

Me too. Hiding is always de-activating from sceneeditor.
Dissolve and other transparency, clipmaps will always be evaluated by the renderer afaik even kray and fprime does it.

Yes that's old "known" thing even for native renderer, If you have 100 lights in scene, put them to 0% intensity scene will render slower than if you just deactivate them in NSE . So in that regard octane is "in sync" with LW rendering so it's good thing .

But nevertheless it's good info to share, thanks.

gordonrobb wrote:Maybe it's me, but I would always use the scene editor to remove things from rendering. Why would you use 'dissolve' or 'invisible to camera'? anyway.

I'm wanting to have an automated way of making luminous polygons 'inactive' when out of shot so they don't compete for irradiance samples and suck the life out of the in-shot lumigons. I'm using nodes connected to the emission 'power' driven by camera ID, so when I switch cameras only the lumigons in-shot of that camera have sampling power, and all others set to zero power. Works well but I found it's still renders quicker if the lumigons are set as inactive in the scene editor.

If anyone knows how to automate items' active state in the scene editor based on active camera ID please share!

Lewis & Geo interesting what you said about the native engine working the same way it's something I never noticed before.

gordonrobb wrote:Maybe it's me, but I would always use the scene editor to remove things from rendering. Why would you use 'dissolve' or 'invisible to camera'? anyway.

I use invisible to camera to hide lumi panels that may be in the shot (tricky reflections on product shots). Not such an issue in LW/Kray/FPrime with single sided polys.

Dissolve is handy when you have multiple copies of a single lumi panel and want to reduce the brightness of one of them.