How to Add Photos to Curved Surfaces in Google SketchUp 8
How you go about mapping an image to a curved surface in Google SketchUp depends on what type you have. With that in mind, curved surfaces fall into two general categories:
Single-direction curves: A cylinder is a classic example of a surface that curves only in one direction.
Multi-direction curves: Terrain objects, saddles, and curtains are all prime examples of surfaces that curve in more than one direction at a time.
The "adjacent faces" method
If you need to paint an image onto a surface that curves only in a single direction, you can use this technique.
Choose View, Hidden Geometry to turn on Hidden Geometry so you can see the individual faces in your model.
Load your cursor with an imported image.
Paint the leftmost sub-face entirely with the image.
Your curved surface is composed of sub-faces. Here’s how to paint the right one:
Hover your loaded cursor over the lower-left corner of the sub-face farthest to the left. Don’t click yet.
When the image is oriented in the right direction, click once.
Click again on the upper-right corner of the same sub-face.
Use the Paint Bucket tool with the Alt key (Command on a Mac) held down to sample the texture (image) you just placed.
With the Paint Bucket tool, click once on the face immediately to the right of the face you painted in Step 3.
Keep painting sub-faces until you’re done.
Remember to work your way from left to right; skipping a sub-face messes up things. To fix a problem, just Undo and keep going.
The "projected texture" method
For painting an image onto a complex curved surface, there’s literally no substitute for this method. Chunks of terrain are good examples of complex curved surfaces. If the curve you’re dealing with is more complicated than a simple extrusion, you need to use this image-mapping technique.
Create a flat surface that lines up with your curved surface.
Apply a photo texture to your flat surface and make sure that it’s positioned correctly.
Right-click the textured face and choose Texture, Projected.
Hold down the Alt key (Command on a Mac) while using the Paint Bucket tool to sample the projected texture.
Use the Paint Bucket tool without pressing anything on your keyboard to paint the curved surface with the projected texture.
Delete the flat surface that you originally mapped the image to; you don’t need it anymore.
If you’re trying to do this on your own curved surface and things don’t seem to be working, your curved surface is probably part of a group or component. Either explode or double-click to edit the group or component before you do Step 5 and see whether that helps.