Crafting A Detailed 'Next-Gen Boiler' - Part 4 UVMapping
In this tutorial I'll show you how to create a next-gen, game model of an old weathered Boiler, with the help of only one black & white reference image. The tutorial will cover the entire process from Low poly Modeling to High poly Modeling, UV mapping, Textures baking (i.e Normal and Occlusion maps) and Diffuse Texturing. Finally we'll be applying Xoliul's shader in Maya for realtime rendering of the model.
Additional Files/ Plugins:
Now to start with our UV Mapping we need to have our UV editor open. One best ways to have it is in a panel itself, so for that go to Panels>Saved Layouts>Persp/UV Texture Editor. And it will open a new panel on right side of the UV Texture Editor, and on left it will be your Perspective View.
Now we need some basic UVs to work on first, as the default UVs are not possible to work over. So select half of the Motor and then go to Create UVs>Automatic Mapping (1). It will create a basic set of UVs, you'll notice 6 projection planes appear surrounding the mesh, these planes project each polygon face from their position and create UVs. The texture aspect ratio is also maintained with this process (2).
Now inside your UV Editor Panel press and hold "Right Click" and from the pop up options menu select "Face" (1) and you're now in Face selection Mode. So select the center faces of this part (2) and then using "Grow Selection" (Shift+>) make a complete selection of the side polygons (3).
Now inside your UV editor Panel press and hold "Shift+Right Click" and from the pop up options menu select "Planar Map" (1), and it will project these faces automatically from "X-axis" (2).
Now we need to convert our selection of Faces to UVs, as we can move, rotate or scale our UVs in UV selection Mode only. To do so press and hold "Ctrl+Right Click" and from the pop up options menu select "To UV" (1) and it will convert our selection to UVs (from Faces.)
Now first just rotate the UVs to have it's axis in the proper Horizontal and Vertical manner. Then keeping the same UV selection press and hold "Shift+Right Click" and from the pop up options menu select "Unfold UVs" (2) and it will unfold the UVs to have the proper texture aspect ratio (3), as only doing a Planar map didn't calculate the actual 3D shape's aspect ratio.
Now select the open edges on the UVs of the side wall and leave only one open edge (1), then keeping the same selection press and hold "Shift+Right Click", and from the pop up options menu select "Move and Sew UVs" (2). And it will sew the UVs to their respective parts leaving only one open edge. Then move this part out of the "0 to 1" UV space and also rescale the side portion (3).
Now to fill in rest of the parts, first use the same procedure (as in "Step 6") to have the border faces selected, then move the side polygon faces near to these UVs (1-2), and also place the small part's UVs too (3).
Now select the middle rim, and first using the same procedure with "Move and Sew UVs", have the border UVs as a single piece. And then select the side face UVs in UV selection mode and then press and hold "Ctrl+Right Click" and from the pop up options menu select "To Shell" (1). And it will select the complete UV shell, then move it over top of the other side faces (2) as we can use overlapping UVs for this part. Finally duplicate this mesh and replace the older ones with it (3).
Now select the outer rims UVs (and the rest of the UVs) and move them near the other UVs (1-2). And then select the side rims and move those UVs near them also (3).
Now the holder bars of the cylinder, start by applying "Automatic Mapping" first, then start placing the separate UVs aside (1). Now select the UV shell of this part and as these UVs are not visible we'll just overlap it on the front one, so after selecting the shell use the "Rotate Selected UVs Clockwise" icon and it will rotate the UVs clockwise at 45 degree and then use it again to rotate the UVs to a total of 90 degrees (2-3).
Now just move these UVs and place it just over the Front UVs (1), then just move the side walls and place them on both respective sides, then in "Edge" selection Mode just select these edges and use "Move and Sew UVs" by pressing "Shift+Right Click" (2). And finally place them just below the rest of the UVs (3), rotating them using "Rotate Selected UVs Clockwise".
Now we need to have the same set of UVs for all 4 holders, so for that select the Unwrapped mesh first and then select the one which has not been mapped, then keeping the same selection go to the "Mesh>Transfer Attributes" settings box (1-2).
In the options box (that just opened) keep the settings as shown (3), the "UV Sets" option is set to "All" and "Sample Space" to "Component" and it will transfer the UVs of the prior selected mesh to the later selected one (1), considering the fact that the number of vertices and shape of the 2nd mesh is exactly the same. And finally we can repeat the process for other two holders as well.
Now just rescale the UVs to a smaller size and place them near the rest of the UVs.
Now we move on to the base of the cylinder by applying "Automatic Mapping" to it, and then following the usual procedure of overlapping non so visible parts, and connecting UV edges by using "Move and Sew UVs".
Follow up of the same procedure, Sewing UVs and then overlapping of the UVs of both the sides, of all 4 sides.
Still following the same techniques to get the various part's UVs done.
Now just move and Rescale all of this mesh's UVs and place them near the rest of the UVs.
Now moving onto the Concrete base, first apply the "Automatic Mapping" and then just use the "Toggle Shaded UV Display" icon (1), and you'll get shaded UVs in your display. The "Light Blue" color depicts "Normal UVs" and "Red" depicts "Flipped UVs". There are more colors also which can be done using the different combinations of these UVs, i.e. Normal + Flipped UVs = Magenta Color or Flipped + Flipped UVs = Dark Red Color, etc.
Repeat the same process of UV mapping on the next Concrete base and overlap a few faces, like the top most ones and the inside ones as these are the ones which are not gonna be visible much (2-3).
This mesh's Unwrap was done the same way, selection of the UVs are shown for separate parts along with the mesh.
Then the complete Control Panel Unwrapped using the same techniques and placed carefully side by side. And the selection of UVs shown along with the mesh to get the idea.
Follow up of the same mesh's UVs to give you an idea of the process/layout.
Now the small Motor on the left side is unwrapped using the same techniques, and below is the selection of UVs showing their respective parts in the Perspective view also.
Now the follow up of the same motor, selection of UVs along with their respective parts in the Perspective view.
Few more parts UV mapped using the same techniques, shown below is their respective UVs.
Now the UV mapping of the screws, done using the same techniques. Unwrapped one first and then using the "Transfer Attributes" option transferred the UVs to all the others. I just kept three different UVs for all of them to have a little variation between the textures. Do the smaller one's the same way (with 3 variations) and finally overlap only two from each. That way we'll have a total of four different variations to work with, placed randomly.
Now we'll move to the small wires as there are lots of them, so select these faces and press and hold "Shift+Right Click" and from the pop up options menu select Mapping>Cylindrical Mapping (1). A mapping gizmo will appear over those faces and then select the green colored cube (2) and move it to the end point on it's cylindrical trajectory (3).
Now select the open edges in the UV editor and select "Move and Sew" to attach them, then select all the UVs of this part and press and hold "Shift+Right Click", from the pop up options menu select "Unfold UVs" and it will automatically unfold all the UVs to it's actual shape.
Repeat the same procedure with the next set of faces and straighten them.
Now we have to attach these two meshes in the UVs, so in "Edge" selection mode select these edges and press and hold "Shift+Right Click" and from the pop up options menu select "Move and Sew Uvs" (1). Then select the lower Uvs only (2) and do an unfold Uvs (3), and using the same procedure unwrap all the wires and place them overlapped as the textures will be the same (4).
Now we have to create the UV layout that consists of all the UVs. As we have decided to have only one texture page of 2048, we will have to fit all the Uvs on one page only. Keep in mind that this stage is one of the most important stages as we get to decide the pixel aspect ratio of each and every part. So we'll start by moving parts here and there to make them best fit into the "0 to 1" space.
Select all the Uvs and scale them down a little bit so that everything can be fitted properly. And then again carry forward the arrangement of the Uvs.
Continuation of the same rearrangement of the UVs.
Arranging some of the smaller parts carefully, not letting them overlap the other parts as this will cause pixel bleeding.
Now just switch on the "Shaded UVs display" option to see whether the Uvs are overlapping or flipped. So this way it will be easier to get our arrangement done faster, and with less mistakes.
Arrangement of smaller parts, fitting them in between the gaps to best utilize the complete texture space.
And that is our Properly UV mapped model, good enough to start with the texturing. Here is the final UV layout.
That concludes part 4!
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