Looking for some help regarding models and light maps

Hey everyone, first off I want to say I’m kinda new to unreal engine and I switched from unity to this because I have more at my disposal. Anyways to get straight to the point, I have some questions that i’ve searched everywhere but couldn’t find a direct answer.

My questions are:

  1. When I model whatever it is I’m modeling, for example a house since the level I’m building requires it. Should I model the house as one mesh? OR should I model each piece individually and then join them together as one mesh?

I’m not sure about the last question because I heard if certain pieces are not connected that light maps can cast shadows randomly from them.

  1. I’m using blender as my modeling application currently and it does a great job. However when I make a 2nd UV channel and create a new texture image to bake my light map. Do I need to use that texture image i baked to in unreal 4 or is it just the coordinates of my UV’s in the 2nd channel that matter?

The reason I ask is because I have a lightmap texture that I baked to but idk how to connect it to whatever object I used to bake. I deleted the texture lightmap that I imported(the one I baked to) and it didn’t really change anything however I still have my 2nd UV channel and it seems as if UE4 handled this for me. However I don’t have generate light maps on so i’m not sure.

  1. I’m working on a sidescroller project using the template as a base for now. Would you recommend using BSP cube for example for the flooring? I made my own flooring but its very basic(a cube with only a top face and a front face for the wall).

  2. Is it possible for me to make a simple action sidescroller with just the node editor(blueprints)? I’m not much of a coder, I learned C++ for about a year but I haven’t really learned how to actually make anything complex however I can read code and understand it.

Once again thanks and I hope anyone can help me out with these questions. I just want to move forward with my project and now I think I have to remodel all my houses again because well they are ONE mesh but each piece is separate. For example the windows of the house are separate as well as the door and wood frames but they are all joined together. I don’t know if this will affect my lightmaps or make weird shadows.


welcome to forum:)

1: there is too many factors for anyone to say really for example if the house will be enterable/how big it is/how many houses there are…, I’m sure people could give you more/better advice on that if you give some more info though.

2: you don’t need to bake light maps in blender as it’s done in UE4, you only need to set up your second UV for the light map in blender.

3: BSP’s are usually only used to block out levels and then switched out for meshes later, using static meshes straight away would probably be quicker and easier for a simple side scroller.

4: yes you could make a simple side scroller with Blueprint’s, actually you could probably make a complicated one if you wanted.

hope that helps:)

Too many pieces can be bad, and so can too much data in one object.
Think of this like a texture map where you are comparing a 16,384x16,384 texture map’s performance to 16,384 1x1 images. Both of these would be pretty stupid when you can achieve the same results with 8 2048x2048 textures, which isn’t as many drawcalls as 16k files, and the resolution per file is also well within GPU and Graphics API processing capabilities.
You want to find a nice balance based on your target hardware.

Hey guys thanks for the replies as it really means a lot to me. I’m glad to have a majority of these questions answered as it makes me think less and just start doing something. By the way what I mean about the house is shown in the pictures below. Notice how one picture shows the house split up in different pieces and the other shows the house fully joined together as one mesh.

I just wanted to know if joining the pieces together like this would cause a problem. I did an import I think a while ago and I don’t think I found any problems although I’m not sure. The reason I ask is so I know whether I need to remodel everything or just edit what I have so I don’t waste time. Details will be added with textures after however I might go for something a bit cartoony and semi-realistic? I guess.

when u export from Blender-and didnt check (selected)- u exported all pieces as own, then in menu onto importing to UE u will see ask- combain ?-if check it- u will have yur mesh as own object, if not chek- all piceses will as separate whith unic name, but thay will take holdplace as unic orient in wiuport)

As Slava said you’d need to combine it into one mesh otherwise in UE you’ll have individual parts for the “roof/walls” and the windows/trim/door. So long as all that is combined into 1 mesh it will go into UE as one mesh. Joining them like that will not cause a problem (unless you were planning on opening the door, in which case that would benefit from being seperate.
For light maps just ensure there are zero/minimal visible seams on your model. I’ve always created the lightmap UV’s for my models myself, i’m not sure how UE handles Auto lightmap generation.