Node setup to render both sides of a polygon? (while 'double sided' is UNchecked)

MrFurious

New member
Wonder if it's possible to have LW render both sides of a poly even if the 'double sided' flag in the main surface editor is unchecked?
 

Sensei

TrueArt Support
When renderer is checking ray-triangle intersection the first thing it's doing is checking whether there is double sided flag in surface..
If it's cleared, ray is passed through without incrementing ray recursion counter, and hitting ray recursion limit.
Any evaluation of nodes, would require incrementing ray recursion.
So no, it would be bad idea. It would slow down rendering.
 

MrFurious

New member
So therefore having the surface as double sided, weather it be through nodes or the surface editor checkbox, would effectively have the same impact on the render engine in terms of ray recursion etc?

If that's the case and there's no difference.. I'd like to find a way to do it via nodes. This is because having high density poly objects in layout with double sided surfaces slows down openGL performance a lot. If I UNcheck all the double sided flags for all surfaces for all objects the openGL performance gain is huge. Then (if possible) I could setup double sided in the node editor but only for those surfaces requiring it.

I found generally scenes render faster when the double sided checkbox is cleared
 
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Sensei

TrueArt Support
It would be possible to make plugin which is setting/clearing double sided for all objects all surfaces, in one key press.

If I UNcheck all the double sided flags for all surfaces for all objects the openGL performance gain is huge.

Exactly twice.

That's why this feature is default off..
 

MrFurious

New member
It would be possible to make plugin which is setting/clearing double sided for all objects all surfaces, in one key press.

I think that's already possible without plugins, just select all surfaces and uncheck DS? Unless I'm misunderstanding you.
 

Sensei

TrueArt Support
But you have to go to Surface Editor, toggle By Objects, select all surfaces, then toggle.
I am talking about press Layout Generic button "Double Sided All" or "Double Sided None" and voila.
 

jeric_synergy

Axes grinder- Dongle #99
Wonder if it's possible to have LW render both sides of a poly even if the 'double sided' flag in the main surface editor is unchecked?
I'm pretty sure, like Sensei says, you wouldn't get any render speed advantage, as the same operations would have to be performed to make it render correctly.

Unless you have a very special situation where you want some rays to ignore one side of a poly and not the other.

Why would you want this?
 

MrFurious

New member
I always use toggle by objects anyway so really it's only 3 clicks for me. But actually I need to have double sided rendered in F9/VPR for some objects like tree with many leaves, but at the same time not have them as double sided in openGL.

- - - Updated - - -

Not wanting a render speed advantage but an openGL speedup
 

Kevbarnes

New member
This is because having high density poly objects in layout with double sided surfaces slows down openGL performance

You could try saving a 'Surface Library' of your objects. one with all surfaces single sided
plus a library with chosen surfaces double sided - one RgtClick then Load surface ................ ok, its 2 operations!

but you would be able to swap-out at will
 
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