Architectural Visualization and Light Maps workflow

Hey guys,
I’m not sure if this is the right area for my question but all the Archviz guys are sitting here, so i try it here…

I saw so many amazing Architectural Visualization so far here on the forum and i’m asking my self all the time how you guys are handling the light maps for thoose big poly models?
Almost all archviz clips and scenes have really clear baked lighting, no light bleeding etc… on chairs, sofas etc… As soon i start to chamfer / turbosmooth a model, the lightmaps within UE4 are looking
just horrible. So would be nice if someone can tell the terick behind the good light maps.

The most simple solution will be to increase the lightmaps, padding betweenthe UV Shells etc… but for big couch 30.000 tris, it’s still not working…

Hi Adik, I think that the only solution for high polycount objects is to split the mesh in different parts ( seat cushions, backrests, armrests…) and then group them inside Unreal

ok, thats a good idea and good start!
I alreday tried this before but every model even with just charmeferd edges above like 1000 Tris starts to make problems when it comes to light maps.
The problems are starting wih curvy, organic models, even when spliting them up, i was never able to get a 100% clean light map.

Working with low poly objects on the other hand is not a problem, using a low poly with normals “baked from a HP” gives me like 100% clean light maps. Aslong the LP mesh isn’t made from a lot of parts or let’s say polys.

Did you try watching some UV mapping tutorials on youtube (making seams, splitting UV islands etc)? For nice results, you have to make the lightmap uvs in your model program (Blender, Maya, 3dStudi etc). Having UE do the auto-unwrap for chairs / sofas etc will never lead to good results.

I’m familiar with creating light maps in max, thats no the problem. For simple game assets it works just fine. The problems are starting when i try to bring higher poly models into the engine, with chamfered edges or even HP turbosmooth models.

Do you have some images?

Maybe the lightmap UVs are just fine and the issues lie within the lighting/rendering settings.

What lightmap resolutions do you use?

For testing meshes i’m uising simple Directlight “sun” and skylight. For a door frame which has around 1000 tris, i tested so far 256, 512 and 1024 lightmaps.
The door frame lightmaps are not so bad, they look ok but they have some small imperfections. I will post later other shots, with other meshes, where the lightmap imperfections are bigger.

For the door frame, when uisng a darker material, basically this would fix a lot or at least make the dark spots not really vissible. But i simply love to work with bright / white colors.

Maybe increase lightmass quality settings? Set bounces to 100, quality to 10, smoothness to .75 and check if it’s better.

I will try it right now, i’m curious how long the building time will be by increasing the lightmass settings…

Just for your door frame, not so much but for a complete scene it could increase it a lot. Still worth it imo. After the bake you are free!!!

For the most complex objects, sometimes I set them to movable. That way you don’t have to unwrap them since they won’t use a lightmap. If you know that your door frame won’t receive the shadows of another object, you can try to leave it on movable.

The door frame was just a example, this lightmap, dark spots, lightbleeding is happening on a lot of my models. The problem with setting objects to movable, ist that they start to look unrealistic.
The last thing i will try is to setup the uv shells pixel acurate, i’m just looking around to find a tutorial on how to setup max uv layout for this.

Chamfered objects are always tricky to lightmap and, as chamfered edges do add to realism, it’s also a common problem. My general workflow is to create an object, unwrap UV1 and UV2, then chamfer, then relax the UV’S down. It’s not always going to work perfectly, you may have to see where the chamfered edges end up and tweak from there (i.e. if a piece doesn’t relax well, unstitch the edge and stitch it somewhere else.) If you keep this as a stack in Max, you can at least go back and change it if, for example, you make the chamfer too big or want to cut down on polys (though you will have to redo any work above that modifier in the stack.)

You can set up an exact pixel grid on max with the options, which will then allow you to keep a gap between islands (I think it’s around 2 pixels?) You’ll need to know the light map size you intend to use however, so you can then calculate the grid block sizes (i.e. if 256 lightmap, divide 1 by 256 to get the grid size). The grid size is in the UV unwrap window options.

With lightmass, you are going to have to learn to live with small imperfections like that, adding some slight color variation in the texture, and a bit of material detail, is really going to be it even less noticeable,

Many thanks for all the tips! I’m trying right now to optimize my uv islands pixel acurate, and that seems to be a hell of work…

Also if you are going to do the pixel snapping, you need to do power of 2 -2px, here’s a break down of why and how that works exactly.

Cool thanks!
Very interesting, i’m wondering why this tips of creating good lightmaps are so rare, epic should upload a bit more dokumenation or tutorials about creating the perfect lightmap.
I’m reading the very first time about this 1+1 pixel border… that should be left.

In mine I put a maximum of 512, still much work to do but I think you should look at something more than simply raise the Light Map Resolution to cover mistakes.

Separates objects, I put doors, handles, frames, all separately and each with its uv chanel 2.

As JMSC pointed out, you have issues with too little padding and too much stichting. The UV setup needs to be refined a bit.

Stich things that are probably lit, and detach stuff that is probably a shadow area. And give them all more space in between, so you won’t have bleeding or the black borders.