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View Full Version : Accurate PBR reflections and reflection tinting in LW9.6?



Revanto
02-25-2016, 06:28 AM
Hi everyone,

For years, texturing and lighting have never been my strong suit. Substance Painter was a godsend as it uses proper scanned values based on real life materials to give the better illusion of reality in texturing.

At the moment I am doing some testing to see how I can get renders in LW 9.6 to mimic how they look in Substance Painter. Yeah, I know, Lightwave is a Raytrace renderer while Substance is a PBR renderer but it's frustrating having something render how I want in Substance but looking different in LW 9.6.

I know that the next version of Lightwave will have PBR rendering (and also, I am guessing, all the 3rd Powers plugins integrated. Yum.) but until then I want to try to get things to translate across properly at least to a decent degree.

So, I tried a small test in regards a gold texture but things didn't work out. I want to focus on the subject of reflection in this thread so here's what I'd like to know:

1) I used a PBR chart for the colour tinting of the reflections for gold. In Substance it looked fine but in LW the same colour value hardly tinted to the same level as in Substance. I used the reflection node and set the colour value to the one of the chart but to get it to match more like Substance then I have to manually darken the tint colour.
So, which render engine is more accurate based on the same set yellow colour for tinting of gold?

2) Just say that I wanted to composite the tinting of the reflections in Photoshop post process and I wanted it to be pretty accurate (IE no eyeballing it), what would be the most accurate colour value and what sort of layer style and opacity would I be looking at applying?

3) In real life, does gold reflect back the colours around it plus the tinting or is it more like that the colours reflected are desaturated THEN tinted yellow afterwards?

4) OK, this question is off topic and in regards to reflection blurring. In the reflection node you have the choice of reflection blurring. In Photoshop you can set blurring via a pixel value but in LW the reflection blurring is based from 0-100%. For Lightwave, what does the 100% value stand for? I mean how much blurring IS 100% in actuality?

Hope this is not too much but I'd like to be clear with the whole issue as it will help me in terms of rendering things more correctly. Sorry that there are no images but I think that this topic can be covered without me posted any images. I COULD post a comparison between my LW 9.6 and Substance Painter renders but all you will see is that there is a difference in renderings.

Thanks in advance to any help and advice.

Cheers,
Revanto :p

spherical
02-25-2016, 03:23 PM
First thing to do is go into the Advanced tab of the Surface Editor and set Color Highlights to 50% or greater.

djwaterman
02-25-2016, 07:55 PM
I use the roughness-metalness export option from 3DCoat and have developed what I think is a pretty accurate node based solution, typically with this option the metalness map is greyscale with the white bits being the metal. There are other export options but this is the one I've been using and designed the nodes for these type of input maps. I've been getting results that match pretty close what I see in the 3DCoat previews (barring the different environment maps and lighting between the two apps).

If you think your output maps are roughness /metalness workflow then I can try them out for you.

These are the maps I get with that workflow

AO map (I don't use it though)
Color map
Metalness map
Normal map
Roughness map

If you use these sort of maps you could post a sample object and maps. Like a simple low res version of the type of surface you are trying to achieve, I mean the image maps don't have to be hi res.

djwaterman
02-25-2016, 09:55 PM
Also, 3rd Powers tools will not be integrated as far as I know.

Revanto
02-26-2016, 04:48 AM
I did a little bit of testing and I found out that the reason why I wasn't getting the same results in LW is that I was using the wrong HDRI image without realising it because the HDRI images I used in both programs were similar.

Anyway, here is the result of the comparison...

https://www.dropbox.com/s/n27k43gn6yw1k4l/_ChilliHead_SubPaint_LW_Compare.jpg?dl=0

I had to make adjustments but they are pretty close. In terms of realism I would need to tweak a bit like using fresnel, for example.

My questions 2, 3 and 4 still stand, though so if anyone can help there then I would be appreciative.

In regards to the 3rd Powers plugins, well, Deformation Lattice, one of the 3rd Powers plugins, has been shown in use in one of the preview videos for the next version. This may be a coincidence BUT I swear I saw an offer to buy LW 2015 which included the whole 3rd Powers plugin pack so their actually may be a collaboration. Seeing as to how good the plugin are, I don't see Newtek NOT jumping at the chance to integrate their tools into Lightwave Next.

Cheers,
Revanto :p

S0nny
02-26-2016, 05:35 AM
My questions 2, 3 and 4 still stand, though so if anyone can help there then I would be appreciative.



I think that's because lw9.6 doesn't have the color space profiles for linear gamma correction.
For the other questions:

For 2 and 3, "pretty accurate" is a bit subjective term and depends on so much different factors, like how you build the shader, how you light it, how you post process the image, and so much other "etc", that eyeballing in pp is almost always necessary and more efficient. It really depends of what is your output: what you need to do exactly? For example, a simulation is different than a visual appealing rendering, which is probably different than a plausible pbr rendering.

What you can do is to build up the shader in the best way possible, like using real values from gold, building fresnel curve for each R,G,B for colored reflections (no diffuse color for metals), also the right amount of bump. Really important are different layers of reflection blur and reflection blur falloff because the lack of ggx shader. Use a high dynamic range scene, with correct lights etc. Then you can color correct in pp based on what you need to do with the render with some eyeballing :P

For the number 4, you have to try actually what reflection blur do in lw to unserstand it better, but 100% is almost like full diffuse, so think ref blur like a scale from a mirror like finished to a total matte surface. Keep in mind that it's a pretty sensitive value, it needs high samplings and aa to see exactly what is doing.

djwaterman
02-26-2016, 11:24 PM
In regards to the 3rd Powers plugins, well, Deformation Lattice, one of the 3rd Powers plugins, has been shown in use in one of the preview videos for the next version. This may be a coincidence BUT I swear I saw an offer to buy LW 2015 which included the whole 3rd Powers plugin pack so their actually may be a collaboration. Seeing as to how good the plugin are, I don't see Newtek NOT jumping at the chance to integrate their tools into Lightwave Next.

Cheers,
Revanto :p

You're thinking of the new lattice deformer that will be included in Modeler, and yes they did include 3rd Powers tools once as part of a deal, but that sort of thing happens a lot with different packages and doesn't signal intergration with LW. I wouldn't rule out something like that for future releases beyond this next one though.
Your gold looked like a match to me except yours had more reflection blur.

Revanto
02-27-2016, 04:22 AM
Yeah, I know, I shouldn't use terms like "accurate" or "pretty accurate" because their is no such thing (well, it's all relative). I suppose that eyeballing anything in 3d is must in the end because no matter how accurate a setting may be for a material, there are infinite variables that can affect a scene including, say, the quality of gold, type of grime, different variations of dust and debris, etc....

I did not know about reflection blur falloff. That's interesting. I always assumed that reflection blurring was consistent. I'll add that info to my notes. Thanks, S0nny.

The lattice deformer is something a long time coming, djwaterman. I believe that Maya and Max had it ages ago or something similar. There are tons of great tools that Lightwave could use but, if they don't fix the basics like the friggin' symmetry then I will be frustrated and have to scream like a little girl!

Cheers,
Revanto :p

jasonwestmas
02-27-2016, 06:18 AM
Physical accuracy is a great foundation/ reference (which does speed up look dev), but that's all it is in the world of tasteful art, a starting point. Eyeballing things stylisticly and honestly is a great resource as well as reference of the real world.

Yeah the other apps. that were bought by autodesk have had proper lattices and modifier keyframing for over 16 years now if not longer :) We didn't even have native spline IK untill 11.5 I think. This reconstructing of lightwave is long overdue but since they are doing it now they have far more knowledge and talent at their disposal than ever. At least in my opinion as I have been observing lightwave development from a user stand point for 16 years.

djwaterman
02-27-2016, 06:23 AM
The Lattice deformer is only for Modeler though, not Layout. Toolchefs already have one that looks to be pretty close to the one that gets put into Modeler with the up coming release, it's free to download (https://www.toolchefs.com/?portfolio=modeling-toolset).

jasonwestmas
02-27-2016, 06:31 AM
Which lattice deformer are you referring to?

The third powers lattice deformer and cage deformer are for layout only. Which actually can be used as a modeling tool in layout only.

http://www.3rdpowers.com/index_store.html


edit: Oh the tool chef deformer.