UV Maps and how they appear in UE4 editor

Okay, the title isn’t very specific, mainly because I have no clue what is going on. I’m brand new to everything related to UE4 and 3D modeling so I decided to start with the basics. A primitive plane.

This is the floor model from the “Reflections” map. It looks pretty nice and clean. I’m assuming all the Tris and Verts for a simple object are for vertex painting? Either way, I’m not worried about all that yet.

So I create a basic plane in MODO. Here is the UV Map for that.

However, as soon as I bring it into the engine and add a material to it, this happens. The left model is the “Reflections” floor. The material tiles perfectly. On my model (the right one) it’s kind of big.

So I double the size of my UV in MODO to cover the entire UV grid. Now I get this.

I mean, it works… I have no problem with that. But the UVs on my model now look like this in UE4

So, if it works, it works. I have no problem with that if it’s not going to cause me any problems later on down the road. But I really want to understand what I’m doing before I move on so…

Why do my UV’s look so vastly different from the one in the “Reflections” map?

Why do both of them have the same outcome?

Sorry for this lengthy post. Thank you all in advance.

You will need to understand the concept behind UV mapping. The reason for mapping your UV in the square template box is so that you could have a reference to your texel space on your model. When we work with texture it’s usually in 256, 512, 1024 squares … and so on. Unless texel space is not so important to you or to the particular 3d object you are working with, you can gladly scale that up to any amount you like. Since UE4 renders light map on index (channel) 2 of your uv map. You will only need to make sure your light map fits inside the square template in your 3d modeling packages.

You first image does tell you that you have overlapping tri going on in your UV unwrap. There shouldn’t be X in your model unless you modelled them that way. I suspect you have overlapping polygons in your model.