Quick Tip #19 : Lightmapping

[@stevefox62]

Just wanted to say thank you! I don't leave comments very often but you're super clear and concise and gave me all the information I needed, really helpful stuff, keep up the good work!

[@WarrenMarshallBiz]

Hah, thanks Steve! Love hearing that sort of thing. :) Thanks for watching!

[@simonemangiapelo6944]

I had been looking for a video like this for days :-) Thanks

[@PrimitiveBaroque]

Thank you for this video. It was very informative. You're a life-saver.

[@rufus8800]

Great video on creating lightmaps. The practical tips you outlined are hard to find topics. One thing that I've been looking for is how to create the UV0 and UV1 maps (texture and lightmap) in MODO for export to Unity or Unreal. I'd assume the UV export process would be the same for either game engine. In your video, you went straight to UE4 and skipped the export step. Is it just a single UV map for both texture and light mapping and then an export using FBX? Thanks.

[@WarrenMarshallBiz]

I make 2 UV maps ... one for the textures and one for the lightmap. And then, yes, export to FBX. That works for both Unreal and Unity. Hope that helps!

[@rufus8800]

Do you need to do anything special to identify the UVs? Example, you have the texture and lightmap UVs and the texture UV has overlapping shells.

[@WarrenMarshallBiz]

In MODO, the uv maps are separate maps in the list. So there's nothing special to be done. I just name one "Texture" and the other "zz" (my lightmap) and they export in alphabetical order so 0 = texture and 1 = lightmap.

[@elk_h]

hi Warren! after watching both parts of the lightmaps videos again. I'm curious to know if you changed your workflow? Are you still packing using IPackThat with the settings described in this video, and then in UE4 just add 2 to the resolution to compensate for the lightmass reservoir thingy?

[@WarrenMarshallBiz]

It depends on the prop. I sometimes will pack by hand to make sure the texels line up correctly to minimize seams. But if it's something small or the seams are already hidden on the model then I'll use iPackThat ... Modular stuff usually dictates a more controlled approach.

[@WarrenMarshallBiz]

And when I pack by hand, I set my UV grid to 62x62 and pack onto that. Then I can use the default 64 setting in UE4 without a problem.

[@TbagsGamesInc]

Are lightmaps only for static meshes? Would I need a lightmap for a sword that is in the players hands that will be contantly moving. Would that need real time lighting or a light map for the mesh? Lightmaps are still on my to do list lol

[@WarrenMarshallBiz]

+TbagsGamesInc Yes, lightmaps are for static objects. Objects that move have to use dynamic lighting or they won't look right.

[@TbagsGamesInc]

Thought so, thank you!

[@world4jack]

based as hell looking like the prodigy firestarter and spilling beans on knowledge which is really tricky to Find out more about. There are pockets of Cg like that, i notice. I guess maybe the tech has moved at a fast pace , so 'antiquated' subjects and approaches toward Cg of just yesterday fade away from search index. Even if they still have place in today's playing field. The bit where go into the how what why of padding was great, thanks for sharing your approach and your time

[@WraithDesignz]

I'm curious on one part. You said you made your own lightmap templates/checker patterns for different lightmap resolutions? How would i go about making those in Photoshop? Bit of a noob on that lol. I want to make some for a few different resolutions as well. Is there some easy fast way to create one in Photoshop? thanks! :P

[@WarrenMarshallBiz]

It's nothing fancy. Just a grid of colored squares. :) Mine are available for download if you don't want to make them ... expand the video description.

[@WraithDesignz]

Wow! I feel pretty dumb now ha ha. XD thanks! yeah this helps me learn how to do lightmaps the best so thanks for the vids man! I been ripping my hair out trying to fully understand them. Your video helped me big time and these templates are awesome help tools.

[@Almajtek]

great tip, thanks! off topic: do you convert your meches from quads to tris before imported them to game engines or you just let the game engine auto convert?

[@WarrenMarshallBiz]

+Alcino Major Ugh ... well, I SHOULD be converting them to tris before exporting but the truth is MODO and UE4 appear to be on the same page about how to triangulate a mesh so I don't. I don't see conflicts. But in terms of strict, proper workflow ... you should, yes.

[@19reficul]

What happened to the awesome Modo Pack UVs? Is there an advantage to using iPackThat? Thanks a lot!

[@WarrenMarshallBiz]

For lightmaps, you want to be more careful with your UV layout since you need to avoid bleeding and weird seams. So auto packing UVs, in this case, isn't the best idea. Most of the time, anyway...

[@christianavigni9692]

Another great video! Tks Mr. Marshall.

[@WarrenMarshallBiz]

+Christian Avigni Thanks man!

[@ChrisRadsby]

Nice work Warren! Thanks for the tips! Also lightmap templates! Godsend! I used to change my UV grid-size all the time.

[@WarrenMarshallBiz]

+Christoffer “Chris” Radsby Thanks Chris! I'm going to do a follow up video today as someone pointed me towards the reason why my texels weren't lining up the way I expected. We're on the edge of perfect lightmaps! :P

[@musashidanmcgrath]

Great explanation, Warren. Might have been an idea to add a pointer about texel ratio Vs coverage, as I'm sure a lot of newcomers to lightmaps miss this. Cheers.

[@WarrenMarshallBiz]

+musashidanmcgrath Ugh, I thought about that after the video was done! :) I meant to cover that. Like, less lightmap on the backs of things as opposed to the front and stuff like that. I might do a quick follow-up video to cover that. Thanks!

[@musashidanmcgrath]

Warren Marshall There's a lot to cover so I'll forgive your oversight. :) Showing the different approaches to unwrapping different assets would certainly be a video in itself. Large asset unwrap, non-uniform scaling of UV shells, UVs that will always be in direct light/shadow, etc. Yes, a video in itself indeed.... :)

[@remon563]

great suggestion :)

[@TTROPVNR]

First thank you for your great videos. Something bugs me about those amazing archviz render, how do they get such clean lightmaps in those huge houses. Does it boil down to how much ram you have? I have 24 and i feel it isn't enough when i want to do 4k lightmap for floors

[@WarrenMarshallBiz]

No, not really ... RAM doesn't affect the quality of lightmaps. Truthfully, most arch-viz stuff is being done in real time. Getting high quality lighting bakes takes high resolution lightmaps which can take forever to recompile.

[@TTROPVNR]

Warren Marshall i ment ram limit you in the amount of large lightmap you can do.

[@Ash011080]

Hey Marshall, many thanks for sharing these great tips ! The lightmap texture template idea is really great (I will test it out asap): it never occurred to me before, even if I have been doing lightmaps for a long while. I have a question though: knowing that you use iPackThat I was wondering if you ever tweak the UV shells position after iPackTahat has finished its packing, or if 99% of the times you're happy with the way it packs the UV shells. I have been using UV Layout for efficiently packing the UVs (when I can't get a decent Packing in MAya) and even if it's great sometimes I still have to manually adjust some UV shells to achieve a better packing. I still have to watch part 2 video though: heading there now. :D On a side note, because this is my very first comment on your channel (I just found about it like 2 days ago): many thanks for all the great information you shared with all of us ! I went through most of the videos (you made a ton of them!) and I found a lot of great tips. I also really like your nice and easygoing attitude: overall you made some really enjoyable entertainment. All this just to say: many THANKS and keep up the good work. :)

[@WarrenMarshallBiz]

Thanks for all that, glad you like the channel! :) And yes, I sometimes will move shells around after packing. It just depends on what the asset needs. It's a totally valid workflow...

[@Ash011080]

Ehehe I guessed so, thanks for the info. ;) Btw the more I see you playing with iPackTath the more I feel the urge to buy it ... I think one of these days I will surrender and give them my money ! :D

[@jayattic]

Hey Warren! Great stuff again, thanks! I've gotta make some lightmap templates asap :) What I like to do in Modo 10 when I'm doing the lightmaps is put the rayGL on Bake mode and have it bake Ambient Occlusion map in lightmap res (64x64 for example) realtime in the viewport. Then if I know the asset is going to be close to something in the engine (it's a modular wall piece for example) I'll block out some extra simple geometry there to simulate that. (work as occluders) This way you can see the bleeding problems on the mesh and when you move the UV islands you can see the problems disappear realtime :)

[@WarrenMarshallBiz]

+jayattic Cool workflow! Thanks for sharing ...

[@orozcoapaza1660]

Can I ask your opinion about Lightmaps for a 1 Km2 Landscape in UE4 ??? is it worth it ?? consumes too much memory ???

[@WarrenMarshallBiz]

I think in that case the lightmap would have to be so high res as to become, as you said, a memory problem.

[@KLICKSTOP]

Hey Warren! can i setup my grid lines in uv editor for example i want to do 64x64 light map and i set up my grid to 64x64?

[@WarrenMarshallBiz]

Enter a formula for the grid line spacing .... like 1/64 ... and let MODO do the math for you. :)

[@MrRadishface]

Really helpful video, thank you! Lightmaps are one of the reasons why I still prefer using CRYENGINE for my personal projects, as I don't need to worry about them. I really hope that other engines will follow suit in the future.

[@WarrenMarshallBiz]

+Kristijonas Jalnionis Lightmaps are a pain, that's for sure. Will be nice when they are something we look back at and shudder, thankful we don't need to deal with them anymore ...

[@remon563]

oh nice nice :) will you do a video on custom collision meshes ? I am still a bit confused on why some of these meshes are seperate (seems easier to make 1 collision mesh). Btw. it is hard adjusting to baking lightmaps once you are used to CryEngine's realtime lighting (so sweet). If performance increases we might see this in Unreals future (?).

[@WarrenMarshallBiz]

What specifically would you want to see? Like, reasons why you would or would not use multiple collision meshes?

[@remon563]

exactly. Once you know these little things creating art becomes so much more fun :) Some other topic suggestions: - MODO 10.1 Splines / MeshFusion Update - BakingWizard Export (its awesome) - RoundEdgeShader workflow - More Complex object UV, smoothing, lightmap example Keep up the awesome work. Watching your videos is a joy!

[@WarrenMarshallBiz]

Thanks for the ideas!

[@remon563]

just a quick question: how do you change your grid spacing in MODO to i.e. 32 or 64 ? the default value is set to 0.1 which is very confusing to work with.

[@WarrenMarshallBiz]

You have to use an equation ... so, for example, if you want a 64 unit grid you enter "1/64" into the field. MODO will compute from there... HTH!

[@Bodni]

Greetings :) Is there a way to bake the light information into the vertex color inside UE4? BTW You have great tutors, thank you a lot for all of it :)

[@WarrenMarshallBiz]

From inside UE4? I don't think so ... altho that sounds like a potentially useful feature!

[@Bodni]

Thannk you for the sudden respond :) Its unfortunate, that this is missing from UE :( it's essential feature for mobile game production.

[@runeskate]

Love your video! wanted to ask you, I have noticed in some instances there is no snapping to pixel edges needed, and also, what about more organic shapes? (i.e. curtains or clothing) or diagonal edges, what about that when it comes to snapping ? also, how do we know when to separate edges from one another and when not to in these kinds of surfaces? THanks!

[@WarrenMarshallBiz]

Experience and luck. :) Honestly lightmapping is a rough science at best. For organic stuff, you're right, it's not as easy. Sometimes you just have to give it a shot and hope it turns out. Glad you liked the video!4

[@runeskate]

aw man thanks a lot! I am working on this wavy bedding so I guess I'll just have to sweat my way through baking a normal map texture into a bitmap if the lightmap won't work, I am having a feeling that's what will produce the micro lighting and shadow details for organic shapes :( here comes a sleepless night!

[@runeskate]

hmm.. wait on second thought, I might be mixing up things here, perhaps I'll need both after all :'(

[@elliotarmstrong615]

Thank you for the tip!

[@DanielMo0]

You nailed it! Thanks for your videos...

[@WarrenMarshallBiz]

:) Thanks!

[@ReDFragg3r]

cool explain , The Only thing that I don't understanf is that about the texture you've build on photoshop for the checker wich is giving more pixel density ? I don't understand that part with the checker and unit because your grid of UV doesn't match the checker you've buld so please explain me I will read you this time will be more easy to understand II guess :) . I'm frenchy so sometimes there are some part that I dont understand clearly ^^ plus : iPackThat is better than doing stuff by Hand ? Thanks doing some nice tips .

[@WarrenMarshallBiz]

+ReDFragg3r Well, the checkers are just a visual representation of what the lightmap WILL be once I'm inside of UE4. So if I set a 32 lightmap on a mesh, I can visualize that in MODO by usind the 32x32 checkerboard texture. Does that make sense? It's not doing anything other than giving me a preview or visualization.

[@ReDFragg3r]

ohh yeeah indeed that's make sense , but without using a custom checker? with the basic checker that have 3d app that doesn't work well ?

[@WarrenMarshallBiz]

+ReDFragg3r Sure, if it has one built-in then use that. There's absolutely nothing special about my checker textures. :)

[@ReDFragg3r]

yeah but that the one by default so I have no idea if I can change the tiling ... last question :) if you are making lightmap with one of these number 32-64-128-256 , like if I set up my lightmap for 128 , that's will match correctly if I want to switch the resolution ?

[@WarrenMarshallBiz]

+ReDFragg3r Yep. It's like any other texture. You map all the UVs to the 0-1 range so that you can use whatever size lightmap you want to later on. That's what the 0-1 mapping space was made for.

[@brentlio5578]

Would be nice if it's possible to bake Ambient Occlusion map in UE4 using this lightmap technique. Having Ambient Occlusion map in 3D software usually doesn't work very well when the model's been animated and re-assembled for the game.

[@WarrenMarshallBiz]

+Brent Lio You can't bake AO inside of UE4 but you COULD use the lightmap unwrap to bake AO if you wanted to, sure. YOu'd just have to set up your material to take advantage of that.

[@TTROPVNR]

what is better usually? 1/1 ratio(losing lot of coverage) or full coverage

[@WarrenMarshallBiz]

I think it depends on the asset. There are usually places on a mesh where you can use less lightmap ... like, say, on the bottom or on an interior space that will mostly be dark anyway. So it's up to you to decide which islands should be larger and such. I think a 1:1 ratio isn't usually the best choice on a lightmap.

[@TTROPVNR]

Warren Marshall thanks for answering if i am not mistaken a ration 1/1 is when the uv are very proportional to the actual asset model. I saw in the documentation of ue4 that they recommend more UV coverage than a 1/1 ratio. But it sounds counter intuitive as stretch texture(therefore ligthmap)wouldn't display properly. Pardon me my broken english :)

[@WarrenMarshallBiz]

When I say 1:1, I mean that the texel density is equal across all the lightmap UV islands. If there's another interpretation, that might be what's confusing you. :)

[@KRGraphicsCG]

Lightmapping UVs is a real pain. I am trying to pack ALL of the lightmap UVs for a dojo in Unity, and unfortunately, I will have to clone the dojo and pack all of the UVs into 0-1 so I don't have a crap load of altas UVs when using Enlighten

[@LSZ1318]

Love the vid and your work is, of course, stellar. But quite honestly I tried to apply all that you just taught in my program of choice - 3DS Max - and it was a trainwreck. Trying to carefully place the mesh faces within the proper texels actually yielded the opposite result - horrible black lines at the edges of simple wall planes. When I simply let the steamroller uv script do the work, with a decent .02 spacing, it was perfect. Maybe I'm just doing something wrong in Max vs Modo... ?

[@WarrenMarshallBiz]

Did you watch part 2 of this video? There's a 1 pixel padding that lightmass adds to lightmaps that causes you to have to uv map to, say, a 62x62 grid if you intend to use a 64 lightmap on your mesh...

[@LSZ1318]

Tnx Warren, watched it and that did the trick!

[@BurntFossil]

Absolutely brilliant! Incredibily usefull very good!

[@WarrenMarshallBiz]

+BurntFossil Haha, thank you!

[@TTROPVNR]

thank you

[@chillingoutt]

Great video!! Thank you so much :-)

[@WarrenMarshallBiz]

+chill Thanks chill!

[@Maxschellenberg]

Thanks

[@glowiever]

are you inspired by the prodigy singer?

[@WarrenMarshallBiz]

No, but you're the second person to mention that to me this week. Must be something in the air.

[@MrEssamhelmy]

thanks a lot.. you made my life a lot easier

[@WarrenMarshallBiz]

Lightmapping hurts us all. Glad you found it useful. :)

[@restlessrepete9754]

Hi Warren, nice tut mate ! I have to disagree with changing lightmap settings (in-engine) purely because if you are hired to create assets with included lightmap uvs then you can't ask the customer to adjust engine settings just for your assets. I am currently working on a structured workflow in modo that compensates UE4s lightmap boarder: With compensation from modo: i.imgur.com/rRrWRg1.png 64x64 lightmap grid setup in modo: i.imgur.com/EV5fVbG.png 2 boxes side by side: i.imgur.com/AwCQRbK.png Cheers Pete

[@WarrenMarshallBiz]

Oh sure, you can do it that way as well. Whatever works ... Changing the in-game setting worked for me but your point about client work is totally valid. Thanks for that!

[@moradshebli9562]

The thing is, this is a great video, but for simple objects. I have a full subway scene with chairs and train rails and so many stuff, I literally have no clue how to make a lightmap for it! Can anyone help me, please!

[@WarrenMarshallBiz]

I understand your pain. :) Videos like this are meant to explain the mechanics of what you need to do but can't possibly cover every scenario you'll see in the real world. Lightmaps in general can have larger UV islands since you're not really concerned about hard edges and breaks anymore. Other than that, you'll just have to get in there and experiment. Good luck!

[@LyubomirIko]

There is just no excuses for UЕ4 to get constant errors when all model faces have proper uv separation. UЕ4 must correct this problem absolutely automatic! All it have to do is just repack uv properly according to the inner lightmap resolution! Why this is such a fuzz??? :( I have watched 10 vids for 20 min on this topic, it is absurdly petty detail.

[@WarrenMarshallBiz]

Yeah, man, I hear ya. Lightmaps are awful ... I can't wait until the day they go away for good.

[@vit9233]

damn.. Working with lightmaps is even worst than i have thought.. Why am i even watching these vids, my life just got harder! -_-

[@WarrenMarshallBiz]

For real. The sooner video cards can get it together and we all use real time GI all the time, the better. :)

[@jayattic]

Also, I wonder if this is the reason for the texels not aligning in UE -> www.reddit.com/r/UE4Devs/comments/246whl/the_most_important_thing_about_lightmaps/

[@WarrenMarshallBiz]

+jayattic Wow! That explains a LOT, thank you! I'll give that a look today and see if that's the case. If it is, that explains everything. I'll do a follow-up video.

[@WarrenMarshallBiz]

+jayattic Yep, I just tested it and you are SPOT ON correct. Thank you SO MUCH for that link. I'll do a follow up video today about that. Perfect!

[@jayattic]

+Warren Marshall Ok! I think this should be thoroughly tested though. I haven't tested it out well yet. It's just something that popped to my mind when I watched your video as I had come across that link before but I didn't realize the meaning of it then. I'm currently trying it out. So far it seems the UE4 lightmap density grid seems to line up perfectly but if the UVs are snapped to grid I get bleeding. If I shrink the islands slightly it's fine. I guess it's not a good idea to have UV edges be exactly between pixels..? (btw Seneca's super UV tools has a nice quantize UV's function and also shrink UV function. Quantize works with UV island bounding box.)

[@WarrenMarshallBiz]

+jayattic Yep, testing now. It seems to hold water ...

[@LuccasSchmigel]

Thank you jayattic! And warren.

[@MikiButler]

Let's hope the uv's go away too :)

[@WarrenMarshallBiz]

+Miki Company I think we can all drink to that!

[@MikiButler]

:D