lightmaps?

[aeronmike]

hey guys..
sorry the obvious question.. but the obvious may not be so obvious -wut

well, i learned how to correctly import my models from Blender, using the FBX pipeline. congratulations for me.
i also know how to uvmap the model for creating the texture, import such texture, create a material from it and apply it on the static mesh in UDK.

but I always see people around saying about that lightmap thing used for per-pixel lighting 3D applications (like UDK itself).

the question is:
I tested and it works without it so, why should I use it? what would it influence in my graphics?

MOST IMPORTANT: where I do it?
obs.: using GIMP for creating textures and Blender for modelling.

thanks.

[Snipe34]

I wondered the exact same things even yet I'm not 100% sure but I think the lightmap principle is sth like collision. You add a collision mesh to a complex mesh so the engine doesn't have to calculate a massive amount of vertexes, but for example, a simple collision box around the many vertexes means the engine only calculates the simple box.

Also, seems you're using the latest Blender and I think lightmaps, and collision can be added in there. Otherwise it can be done in UDK. I use an olde Blender so I use UDK for lightmaps and collision and I'm well-pleased with the results. But here's a person who gets seriously stressed about lightmaps http://forums.epicgames.com/threads/...-UDK-lightmaps!

Also, these link may help you:
http://www.worldofleveldesign.com/ca...-lightmaps.php
http://www.hourences.com/tutorials-ue3-lightmapping/

[aeronmike]

wow haha

thanks a lot for the links! I'm sure it'll help me, and your explanation told me a lot. once more, thanks!
i'm gonna read them right now

[darthviper107]

Lightmaps are a texture map of the lighting applied to your mesh. The benefit is that it allows for more realistic lighting than what dynamic lights currently offer. The main deal is that it can calculate how light bounces around, so if you have sunlight coming through a window, it will bounce around and illuminate the whole room just like it would in real life. This takes a lot of processing power which is why it's rendered to a texture and displayed on the model. Another term for it is baking the lighting. The only downside is that it only works for static objects--things that don't move, because if it moves then the lighting would change.
The point in UDK where it gets difficult is that you have to have a separate UV channel specifically for your lightmaps. Lightmaps have specific requirements for how they can be rendered in that the UV's can't be overlapping or inverted, and they have to fit in the 1x1 UV space. It can be a hassle to deal with since to get the best results you would want to unwrap things manually, but that takes extra time and while there are automatic ways of making a new UV channel for lightmaps, you end up getting poor results.