PlyEdit: 3D Paint

There is no painting within PlyEdit itself; what the 3D Paint tool does is provides an interface between PlyEdit and 2D paint programs. The only requirement is that the paint application can read and write TIFF formatted image files.

In this description GIMP, a free multi-platform application (see gimp.org), is used as the external 2D paintbox. Commercial products, such as Photoshop, would work just as well.

The painting process is quite simple:

Fig 2. Select View

1] Select View: Select a view of the polymesh that you would like to paint.

In this situation an Ortho projection may be better than Persp as parts of the polymesh further from the camera will be given the same pixel coverage as closer parts.

Also consider hiding parts of the polymesh that you don't want to paint. Say you have a whole creature, but only wanted to paint the head, hide the rest of the body. This will speed up the color export and import process.

2] Extract Color: Fig 3. Extract Color
Click the Extract button. This writes the color and surface shading into two separate files; by default, out.p.tif and out.s.tif.

To change the filename prefix edit the Name field. To change the save directory, click on the right arrow after the Name field.

Normally the extracted color images are the same resolution as the display window, but if the mesh being edited is very dense, some faces may be smaller than a pixel in size. To fix this, increase the resolution of the extracted images with the Mult value.

The left side of Fig 3 shows the extracted color, a blank canvas because Clear was used before painting, and the right side is the surface shading.

Fig 4. Load Images

3] Load Images: If your paintbox supports layers then load the color file as the background plate, and the shading image as a multiplying overlay (see Fig 4). The shading information can then be switched on and off by showing or hiding the top layer.

If your paintbox doesn't support layers, then all you can do is load the color image. Consider using Recolor before you start painting to get some idea of the location of surface features.

Fig 5. Paint

4] Paint: Paint away, making sure that the background layer is selected, not the shading overlay (see Fig 5).

What you do here is only limited by what you can do in your paintbox. You could even import and overlay images from other sources, such as texture libraries or digital cameras. The only restriction is that you don't change the size or orientation of the background layer.

Fig 6. Check and Save

5] Check and Save: Turn off the shading overlay to check that the color you painted looks OK (see Fig 6). Of course, you can do this at any time during the painting stage.

Once you're happy with the painted color, delete the shading overlay and save the modified color image. Simply overwrite the original file, out.p.tif by default.

Fig 7. Project Color

6] Project Color: Back in PlyEdit, click on Project. The original and modified color files are compared, and any differences (i.e. the pixels you painted) are projected onto the polymesh (see left side of Fig 7).

By default only visible and facing vertexes are updated. That is, you can only paint onto what you can see (see middle of Fig 7). If you want to paint all the way through the polymesh, disable Facing Only and Visible Only before projecting (see right side of Fig 7).

To paint some more, go back to step 1].

Dirt

Fig 8. Dirt

Often realism in computer graphics can be greatly enhanced by adding imperfections to color textures. These naturally occurring features, a result of an object's exposure to the physical environment, can include rain staining, scratches, scarring, bleaching, corrosion and the accumulation of dirt.

Fig 9. Clean and Dirty

With the Dirt tool you can automatically calculate the later; dirt (black) is added to the polymesh color in crevices (see right side of Fig 9).

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 To paint some more, go back to step '''1]'''.
-== Dirt == {{img|PlyEdit-dirt1.png|Dirt}} Often realism in computer graphics can be greatly enhanced by adding imperfections to color textures. These naturally occurring features, a result of an object's exposure to the physical environment, can include rain staining, scratches, scarring, bleaching, corrosion and the accumulation of dirt.
+== Dirt ==
+{{img|PlyEdit-dirt1.png|Dirt}} Often realism in computer graphics can be greatly enhanced by adding imperfections to color textures. These naturally occurring features, a result of an object's exposure to the physical environment, can include rain staining, scratches, scarring, bleaching, corrosion and the accumulation of dirt.
 {{img|PlyEdit-dirt2.jpg|Clean and Dirty}} With the Dirt tool you can automatically calculate the later; dirt (black) is added to the polymesh color in crevices (see right side of {{fig}}).