I have a large model made in Blender, it is a wall with 3 door ways. I need to add a detailed texture to my door frames for example adding hinges and a strike plate, the issue is that the wall is two big and takes up to much space to create a detailed texture in the UV map. My question is will it effect my lightmap if I add an extra UV, it would mean I’d have three UV’s and I’m unsure if this would effect my Lightmap UV by adding a third? The reason I’d do this is so I can scale the door frames in a separate UV to scale them and detail them.
Also is it good practice to do this or is there a reason people don’t do this?
This would be a Multi-Sub-Object where you can assign different Polygons to different materials/textures. For each material you can us the whole of the 0,1 UV space. However, when you create your 2nd UV channel for lightmapping you would still want the entirety of your object(s) to be in this single space.
I’m not sure if that’s confusing or not. Here is an example (I will put together a picture reference to go along with this in a bit as I have to test something similar with multi materials on an object anyway)
Let’s look at a cube:
There are 6 faces. If I condense them down to 1 material I will have to scale them down if I want them to have unique textures or I can overlap them if I’m using a tiling or seamless texture because I know this will work out OK.
If I chose to instead assign a different material to each one of those faces. That would mean I would have 6 materials. Each one of those elements/materials can use any portion of that UV space without affecting the other 5 faces with different assigned materials.
Doing this is a great way to have multiple materials and have a greater texture resolution for your objects!
All of these textures will be on your first UV channel for your textures! So no need for multiple UVs even though it would be treated that way!
The second UV will still be for your lightmap. You will need to make sure that your object has no overlapping UVs here and that all 6 faces are within the 0,1 space.
Okay, I’m back with the image setup to hopefully explain this a little bit visually.
There are 5 images within this one image. If it loads too small just open in a new tab and it’ll go to full size for a clearer resolution.
I’m going to list here in image order:
The setup. This is a multi-sub-object material that has been applied to a cube. There are 6 materials/textures that are applied with this material.
This is the cube I’ve created with it’s UV layed out
This is multi-sub-object material (3ds max, may be different in other programs) you can see there are places for a lot of other textures to be put into the slots!
I setup the multi-sub-object material to be color based for easier reference, I’ve selected a single face (highlight with red dot), then highlighted the material ID in the multi-sub-object material, then highlighted the ID that is set for that face in my details panel.
You can see the original UVs layout for channel 1 in this image. If you look at the textured face on the cube and how enlarged it appears without re-sizing the UV face. You can see that even though all the faces are in Channel 1 the only face affected by this texture is the face that has that material assigned to it.
Here you will see the same thing. The only difference for Channel 1’s UVs is now that I’ve resized all 6 faces to fit the entirety of the UV space. You can see on the side of the cube how this now can affect the texture resolution!
Multi-Sub-Object materials can benefit larger objects and utilizing texture space in a different way!
Thanks Tim you’ve been great help. I am new to the whole game development thing so I’m sorry if I’m slow or don’t understand some terms used. I do understand the whole concept of a Multi-Sub-Object the only thing I am failing to understand is adding great detail to my various parts of my large meshes.
My object is 28 meters in length so unwrapping the whole object in that UV space has it’s problems, as you can see in the top left of the UV I have scaled the inside of the door frames as large as I can to try and add as much detail as possible however if you look here the door hinge texture is really pixelated:
Any tips on making these parts more detailed? Due to the lightmap importance bug that causes a tiling effect I can’t really create small environment asset’s or I will get that awful tiling effect so the meshes need to be large and I am now getting this lack of detail on my meshes.
In reference to the lightmass shadow seams, the best result here for the moment would be to have another mesh or a corner at any place where the mesh would need to tile. Ie. at the edge of the wall you could have a pillar that comes out from the wall a little bit to hide that seam. This can be a completely different mesh all together.
Okay, now for the initial door frame question:
In the case of this. on the model I would add some cuts to take just the polygon space that is going to be held by the door hinge and since you would have that as a separate polygon cut into your larger mesh, you can assign that inner door frames polygons much differently than having to have the whole of the inner door frame there.
Instead, you could layout your texture and scale up the walls significantly.Overlap the inner door frame (unless its a differnt materail all toegher) with the lower walls to have the same texture. If it’s a different texture I would rotate the inner frame 90 degress and overlap all four of those if they are the same texture. The polygon that is going to be a single polygon for the hinge. I would scale that polygon way up (maybe 3-4 times bigger) to get a good resolution on that smaller piece.
This is a piece I did for my final project a while back. I had nearly everything in this image that is confined to the desk was on a single texture sheet. If you look at the post it notes you can see that I was able to include detail in these by scaling them up when I organized them on my texture.
If you need any other tips or more clarification let me know.
The issue I am now left with is if I add a hinge texture to Face One, the texture doesn’t take up the whole space (which I don’t want it to). So let’s say I add a texture to Face Two in UE4 I could never get the texture of Face One the same as Face Two. I might not be wording this properly however in a nutshell I can’t get the texture of Face One to match Face Two. Is there a way to overlay a UV over another? This would eliminate this problem? Thanks
I’ve made a simple wall with a door and I’ve cut some polygons into it the inner door frame. I’ve done two styles that you could try depending on what you need to achieve.
In the first image you can see my UV layout and how it will affect the mesh in the second image for texture resolution.
In the UV you will see that the two rectangles in the top left of the UV space are the two “hinge” polygons that will be the space for my hinge texture. These are super large compared to what you would realistically want to do them as but it’s just to indicate how you can utilize your texture space. You can see from the other UV islands that I’ve combined the front and back of the wall to overlay and use more texture space.
Here in the second image you want see the inner door frame I’ve created.
The material applied is a checker pattern to make it much easier to see the effect here.
Like I said earlier I cut in two variations (I’ll post those in a comment below so you can see how I did that)
What you’ll see here is that the walls and parts of the door frame that aren’t the two polygons for the hinges are all the same size with larger checker patter. This means their resolution is smaller within the UV space.
The two polygons that are the hinges are getting a much higher resolution by having scaled them up in the UV space. You can see this because there is more of a checker pattern in the polygons space meaning it’s using more of the UV space to get a higher resolution.
Here I’ve attached the image of the two hinges. You can see I used a different approach to each. One I kept flush against the wall and the other I cut into the middle of the door frame. Either would work fine depending on what your ultimate goal was and how it fit into you game assets.
Using the original squared off hinge would probably have worked well for that. For this. What you may want to do is have a separate small mesh that is layed on top to be your hinge. I’ve made a quick demo in the images below to demonstrate this.
To do this, I found an image on google that was similar to what you have. I made a simple plane that was the resolution of that image then scaled it down to the relative size I needed and essentially cut the geometry I wanted to have on the door. The last image is the geometry without the extra fluff.
If your diffuse texture is going to include the hinge. Go ahead in photoshop or whatever image editor you use and put the hinge imagery on there. Make a plane in Blender that is the size of the diffuse texture you’re making. Place this texture on the plane and cut the geometry out. You can attach this to your wall mesh to make this much easier to manage.
To add a little extra detail you can extrude the edges out just a bit to give it some depth and not look like a plane sitting against a wall or even to have any z-fighting polygons that will cause problems.
