IRay Glossy Roughness
marble
Posts: 7,500
in The Commons
Is there a reason why so many PAs set the Glossy Roughness surface parameter to maximum? This is often allied with a very high Glossy Reflectivity and often pure white Gloss Colour. None of that makes sense to me so I end up going in and turning down those values. The main problem with such a high Glossy Roughness setting is that it makes viewing in OpenGL very difficult (in the viewport).
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if there's a texture map driving the roughness then maximum is the correct setting
If you set the Per Pixel Shading option to ON in Preferences>Interface, you will see it better in OpenGL viewport.
Thanks for confirming that but I don't get why. Perhaps it is just my eyes but it doesn't seem to make much difference (if any) in the render if I turn it down.
Turning that ON is the opposite to what I have been advised to do in the past. I should try to find an explanation of wht PPS does and what are the consequences of having it ON or OFF. However, you are quite right - it does look better with PPS ON.
By the way, this skirt does have a texture map in the Glossy Roughness slot.
If there's a map in place then Glossy Roughness becomes "Use Map/Don't use map" a simple ON/OFF. Though you still have the option to turn it down if you don't like what Stonemason is giving you.
I didn't have a Stonemason set loaded so this is not about any particular product or artist. I mentioned it because so many items were difficult to work with in the OpenGL viewport until I turned down the Glossy Roughness. Now that I have been given the advice to turn on PPS, that seems to be an instant solution. I'm not sure why the advice in the past has been to have that turned off though.
The two images of that skirt (above) are examples of what I mean but there are some items of clothing that glow so much that it is impossible to see any detail.
Ahh, now I can see the downside of having PPS turned on. Here are screenshots of G8F and G3M in the viewport with PPS ON and OFF - the difference with G3M (Base figure) is remarkable (and it looks nothing like the IRay rendered skin).
Apparently I've never tried turning PPS on, because that's what those figures have always looked like to me.
Just checked and the base G3M comes with a 3Delight skin by default so that is the reason for the huge difference in the viewport. Change that to any IRay skin (still with PPS ON) and it does look more like the rendered image.
The final value for the property is obtained by multiplying the base colour and the map together. White is the identity (like multiplying by one) so if the colour is white the map is used literally, if you use a darker colour (or non-grey colour) then the final value will ot be the value from the map - which is not usually the intended result.
Thanks for the explanation, Richard. I will experiment with PPS turned on but, in the meantime, can you explain why it might have been advised to have it turned off?
So far, after a few experiments, I think I may go back to having PPS turned off. With it on I get strange effects when there is an opacity map (when cloth is semi-transparent, for example). Also there is no indication of gloss at all. I guess I will just have to go back to turning down the Glossy Roughness even though I might need to turn it back to 100% for the render.
I have never used the OpenGL view as an indicator of anything (shaders wise). If I want to see how roughness looks like I just use the Iray preview, so I don't care about the OpenGL inaccuracies as long as it doesn't hurts to look at.
Yes, that's what I do too but I have got used to seeing the OpenGL image and judging somewhat how it would look in IRay. But yes, I hop in and out of the IRay preview all the time now that I have a GPU capable of doing that without slowing down my workflow too much. I was not happy with the Filament preview either so I actually prefer OpenGL for the viewport even though it is ancient and so very limited.
Back in the early 2000s, when PPL/PPS was a relatively new thing, GPUs just weren't nearly as powerful. The comparative overhead in a more modern card is pretty negligible.
how do you make a roughness map?
i'd like to make a few for my colder characters. like aiko3
So what is the rule when using roughness maps? Pure white in the Gloss Colour and what about the other Gloss sliders? Are Roughness and Reflectivity always maxed out?