Baselightmass.ini. Do you still use it?

[melvixo]

So now we have lightmass portal and embree added to speed up rendering time but I wanted to ask if any of you still tweak the baselightmass.ini. Do you still feel the need to use it or the world settings parameters are enough to give you quality results that rival offline renderers like vray/corona?
I also want to ask about using skylight only, Is that still one light bounce or u need a direct light source with low intensity to simulate better light bounces or skylight has been improved to multiple bounces?
I am currently studing Daniel W's notes about what the parameters in the baselightmass.ini. For those using the .ini paramters are the results better compared to using only the world settings? because I have tried the world settings, and I don't think the quality is as I would want.

[heartlessphil]

skylight+hdri with stock .ini work just fine.

Some test for my kitchen configurator. This isn't even highest quality. Temporary lightmaps, lightmass quality 2 and 1 big portal. Only the skylight with a neutral grey hdri. Artificial lights are going to be set to movable if I include any, to prevent artifacts. Took 45 mins to build on one i7 and 25 mins with two i7. Lightmaps resolution increase render time the most I think.

[melvixo]

Hi heartlessphil, nice work

What is stock.ini? When u say lightmass quality are u refering to the indirect lighting quality in the world settings editor? That you left everything in world settings and baselightmass.ini at default except changing Indirect lighting quality to 2? what about Indirect lighting smoothness? won't you need to reduce that to get better shadows? I do feel like since your scene is one room with a big window, lightmass setting won't require much tweaking. Getting good results is very scene/level dependent. If you have a complex floor plan with multiple doors, small,medium and big windows, would this still work efficiently? I am still practicing so I may be wrong?
Also, can one tweak the lightmass.ini on a project bases rather than the baselightmass in the engine folder?

[heartlessphil]

Yes you are right, by stock I meant default.

My lightmass settings in world settings are :

Scale 0.15 / Bounces 20 / Quality 2 / Smoothness 0.6 / I'll update with better images soom, I'm finishing the kitchen details.

You are right, settings are scene-dependant. A more complex apartment could require some tweaks but I always start with a plain hdri in a static skylight. I add a sun (static) and artificial lights (movable) as needed. I use lightmass portals in every opening. It's when you bake many different types of lights that the problems seems to appear in my experience. You know, baking the skylight, the sun, spotlights etc.

[melvixo]

Thanks for the clarification
I am guessing the more complex the scene, the more base lightmass.ini settings would require tweaking?

Also the line on the wall, are you using a normal map, bump offset or parallax occulsion mapping or it's modeled? I am also guessing u are using a unsharp mask or tonemapper sharpen in postprocess?

[heartlessphil]

It's a preview scene, it's all geometry. Materials are just a plain color and a roughness value for now. Default post process volume without tweaks at all except screenpercentage 200. Shot from a cine camera actor.
Now I'm debating chamfering every edges or not in 3ds max... It's a pain when doing lightmaps imo.

Do you have multiple pc to use with swarm? Then maybe you can increase the photon mapping quality in the lightmass.ini without suffering overly long build, otherwise i'd skip that for now!

[melvixo]

It looks really nice.

I would just chamfer the edges, if the uvs are properly unwrapped with enough margin, no lightmap issues. rather than having to bake the chamfers into a normal map. 3dsmax needs to get better unwrapping tools imo.

Would try the screen pecentage thingy, I think I need to start using the camera actor to get a better feel of how the scene should look. Right now just using the editor viewport. I am using only one pc. I have been playing with only the world settings and I think I am getting better results. It's all about understanding how light bounces and how you can get/manipulate your scene to get as much as you can. I think that's why Koola's scene looks so good.

[heartlessphil]

I'm not going to bake the chamfers into a normal map, too much work imo. In V-ray/corona we have raytraced round corners which does ''chamfer'' in the shader, automatically. It's awesome. But for unreal I'm gonna either add the geometry or leave it with sharp edges.
Screen percentage is a very nice anti-aliasing method complementing temporal AA. I'C already running it at 2560x1440. With 200% on top of it that makes quite a lot of pixels :-P

[melvixo]

Screen percentage does make things look better. Thanks, mate for the explanations.

[MSL]

With the introduction of Light portals and improvements, most of the scenes don't require any tinkering with BaseLightmass.ini
Though skylight is sufficient in most cases, I do go with a direct light to give a better light shaft effect to the scene. This will also help in getting even illumination in some parts which otherwise will appear very dark.

I'm not going to bake the chamfers into a normal map, too much work imo. In V-ray/corona we have raytraced round corners which does ''chamfer'' in the shader, automatically. It's awesome. But for unreal I'm gonna either add the geometry or leave it with sharp edges.
Screen percentage is a very nice anti-aliasing method complementing temporal AA. I'C already running it at 2560x1440. With 200% on top of it that makes quite a lot of pixels :-P

imo, if the objects are simple enough no need to chamfer edges as long as you have a good unwrap UV. With regard to screen percentage it does improve anti-aliasing and details then again there is trade off with fps.
[MENTION=8112]heartlessphil[/MENTION] Btw, do you experience color bleeding when you introduce more lights into the scene. I have seen slight color bleeding especially from bright colored objects if it is perpendicular to the direction of light (for example, if scene uses Red color for floor and a spot light is introduced as a ceiling light)?

[heartlessphil]

In the scene I've posted previously the bright red ''bleeds'' on the white floor and the side of the counter. I think it's called diffuse interreflection and it's basically a realistic effect. But it's so subtle that once I'll have my textures in place i'm not sure i'll still notice it anymore.

[melvixo]

I think UE4 handles color bleeds fine.
Does anyone know if emissive materials have one bounce or multiple bounces like punctual lights? Say I have a material like bulb in a room, which would be better? A point light or emissive material? Would an emissive material be sufficient to create light for a bulb embeded into a ceiling?

[BlairCW]

Heya Phil, thanks for the info.
When you say 1 big portal are you meaning 1 lightmass portal that encompasses the whole scene, or do you mean one that covers the large opening you have in your demo scene?

[meijervis]

Personally, I dont think its necessary anymore. I just use a Static lighting level scale of about 0.25 for nice contact shadows, and an Indirect lighting quality of 10, build it on medium quality and it comes out almost perfect.
As for lighting, I still prefer the bounce card method over a skylight most time (please dont hate me for this), because it gives good control over how much lighting you want in each room.

[melvixo]

I also think using bounce card is a better approach, to control lighting, achieve better result and getting more photorealistic effect. I do intend to try it out at some point. :-)