Sketchup UV Mapping

Colonel_Klinks’s Sketchup UV Mapping Solution

A W.I.P.

Production

Copyright 2009 - Resentment Publications – http://www.resentmentpublications.com 1

This is a work in progress and things may change/improve over time.

IntroductionWhile SketchUp is a great tool for 3D modeling it’s built in texture mapping feature is not really up to the gaming standards of 3D Studio Max or Ultimate Unwrap3D where the UV map needs to be laid out over one or several texture maps.

The following technique is the culmination of several attempts, all which have to some degree been successful.

This tutorial presumes the user has intermediate to skilled use of SketchUp and understands the concept of UV mapping


Preliminary SetupTo speed up the mapping process I set up the following keyboard shortcuts. Set your keyboard shortcuts to suit your individual needs.

Make Group/Make Component Shortcuts1. Create a cube. Any size will do.

2. From the SU menu Select Window>Preferences.

3. Select Shortcuts and in the right hand pane scroll down until you get to Edit/Make Group.

4. Assign key G as your keyboard shortcut.

5. Close the Preferences Dialog

6. Select a face on the cube and Press key G. This will group the single face.

7. Make sure the face you grouped is selected and go back to the Select Window>Preferences Dialog.

8. Select Shortcuts and in the right hand pane scroll down until you get to Edit/Item/Make* Component.*This selection will only appear in the preferences dialog AFTER the face has been made into a Group

9. Assign key T as your keyboard shortcut.

10. Close the Preferences Dialog

11. Test the keys by selecting another face on the cube

12 Press G then T

13. Select the new Group/Component Face


14. Right Click on it and check that it has indeed been converted. See Fig 1.1. If all has worked correctly you will see the Edit Component selection on the pop up menu.

Fig 1.1Select/Paint Keyboard ShortcutsThe following keyboard shortcuts assist in speeding up the texture UV mapping/painting.Following the procedure outlined above in assigning keyboard shortcuts:

1. Assign key Z to Tools/Paint Bucket

2. Assign Key A to Tools/Select


Simple Mapping – the ContainerIn this section you will create a simple box shape then lay out the components for texture mapping.

Creating the Model1. Create a box 6 meters long by 2.4 meters wide by 2.6

meters high.2. Use your new Make Group/Make Component keyboard

shortcut combination to make each face of the box into an individual component see fig 2.1

Fig 2.1

3. Select all the new objects4. Copy the selection by holding down Ctrl key and drag along

the Red or Green direction.5. Place the copy in a position so that the unfolded copy

doesn’t interfere with the original.6. Unselect the top face7. Select the Rotate tool.8. Select a corner between the unselected face and the next

adjacent face9. Rotate the selected faces 90 degrees until the adjacent face

is parallel to the unselected face. See Fig 2.2


Fig 2.2

10.Deselect the adjacent face11.Rotate select as before Fig 2.3

Fig 2.3

12.Repeat until all faces are on a parallel plane Fig 2.4

Fig 2.4


13.Check that the faces on the copy reflect the original by using shortcut A to select the copy face. Double click your left mouse button on the face and see if the corresponding face on the original is selected. Fig 2.5

Fig 2.5Creating the UV MapNow that we have created the model and flattened the copy of it we are now ready to create a UV Map.

1. Select the Top (Plan) view in SketchUp and turn off the perspective (uncheck Camera/Perspective). I have that assigned to shortcut key Q.

2. Center the unfolded copy in the view port.3. Create a Square plane around the unfolded model. This will

be the base UV map outline and background for your UV map

4. Move the square so that the unfolded model sits comfortably inside the square perimeter.

5. Move the square slightly below the unfolded model along the Blue Direction. You will have to rotate the viewport to do this.


6. Return to the Top view.7. Turn off Profiles in the Line Style dialog so that only the

edges are shown as crisp lines. Fig 2.6

Fig 2.6

Capturing the screen to create a UV Map1. Zoom in so that the layout above fills the SU viewport.2. Either save the view as a jpg or use the Print Scr button on

your keyboard

Preparing the saved image as a UV Map1. Open the saved image in your paint program (Paint Shop

Pro, Photoshop, etc.)2. Select and crop the image to the boundary of the square.


3. Resize the Cropped image to 1024 x 1024 pixels (The gaming industry generally uses a 2x2 image size. E.g. 64 x 64, 128 x 128, 256 x 256, 512 x 512, etc, etc.)

4. I filled each part of the container model a different color to demonstrate the next steps.

5. Save the image as container.tga

Mapping the Image to the Base Square1. In SU select the square and apply a color (I use red, but

which color is not important), to the square. Fig 2.7

Fig 2.7

2. In the Materials Window select Edit.3. Load the container.tga image you created4. Change the image size to the width of the square plane Fig

2.8 ( in my case the Square was 11.825m


Fig 2.8


Align the image in the base square using SU Texture tools

1. Select the square plane face (not the edges)2. Right Click on the face and select Texture>Position3. Move the texture so that the Red Pin is in the Lower Left

Hand Corner Fig 2.94. To accept the changes Double click anywhere out side the

model area.5. Right click on the face again and select Texture>Projected

(A tick will appear beside Projected)

Fig 2.10

Mapping The Model (The fun part)1. To watch the results happening rotate the viewport2. Select the Paint Tool (shortcut key Z)


3. Hover your mouse over the Square and while holding the Alt key click the Left Mouse button. This ensures the paint tool has selected the Projected image, and not the assigned image.

4. Select shortcut key A and double click on one of the component parts of the flattened copy.

5. Click Z and apply the paint to the part.6. Alternate between keys A and Z to paint all the parts. Fig

2.11

Fig 2.11


Texturing the ModelTo make the container textures we use our paint program, the container.tga image file we created for the UV map and apply container-like textures to it. Once that is done we reapply the container.tga texture to the model. Fig 2.12

Fig 2.12


Other Shaped Models

Complex models can be UV mapped using the same techniques. The following are just some of the models I have done using the Make Group/Make Component and unfolding the copied model manually:


To conclude, any shape can be mapped using the above technique. Curved shapes pose their own problems which can be difficult at times.

Complex shapes should always be broken down into workable groups.

Have fun.BobAka (Colonel_Klink)


Documents

Sketchup UV Mapping