Using the Unwrap Operation

There are two methods available in 3D Canvas for painting objects. The individual faces can be painted or a texture wrap can be applied to the whole object or a selection of faces.

Unfortunately, painting individual faces rarely produces good results.  Cylindrical, spherical and flat texture wraps work well with many types of objects, but they don't work particularly well with irregularly shaped objects.

The Unwrap Operation makes it possible to indirectly paint characters and other models in a Paint program like Paint Shop Pro.

What follows is an explanation of how to paint a character with the assistance of the Unwrap Operation. The Unwrap Operation is part of 3D Canvas Pro.

 

For this tutorial we are going to paint a model of a baby. This model is available at a number of web sites that offer public domain models. You can however use any character you wish for this tutorial.

You will want to have an Orthographic view to work with as well as a perspective view.

Select View Selection from the View menu. Choose the upper center icon that shows a single vertical line.

Right-Click on the right view, and select View->Orthographic->Front from the popup menu. Note that front means front of the scene rather than front view of the model.

 

TutorialUnwrap1.gif (22943 bytes)

 

We will not be able paint a complicated object such as this in one step.

We first have to determine what areas will need their own texture map. Once we decide which areas need their own texture map, we mask these areas by painting them a unique color.

For this model we will have texture maps for the body, face, hands and feet. Each of these areas will be painted a unique color to indicate where we will be placing our texture maps.

Set a color of yellow using the Material Palette. Click on the object to select it, then fill the object with the color using the Button-Toolbar-FillTool.gif (941 bytes) Material Fill Operation which is located on the Operation Panel. Yellow indicates the areas that later be filled with a skin colored texture.

Note that we are painting with a color not a texture. Painting with textures can result in increased model points since where there are seams between textures, points need to be split.

 

TutorialUnwrap2.gif (27193 bytes)

 

Click Button-Toolbar-FaceGroupSelectionTool.gif (911 bytes) to select the Face Group Selection Tool. It is located on the Edit Toolbar.

Click and drag with the Button-Toolbar-FaceGroupSelectionTool.gif (911 bytes) Face Group Selection Tool on the orthographic view to create a rectangle that encloses the baby's head. When you have done this, release the mouse button.

 

TutorialUnwrap3.gif (26266 bytes)

 

This selected all of the faces within the rectangle.

Only those faces that were forward facing were selected. If you had wanted to select all faces, you could have Alt-Clicked while using the Button-Toolbar-FaceGroupSelectionTool.gif (911 bytes) Face Group Selection Tool.

 

TutorialUnwrap4.gif (26923 bytes)

 

Use the Button-Toolbar-FillTool.gif (941 bytes) Fill Operation to paint these faces green.

 

 

A number of faces were painted in the previous step that didn't need to be.

 

TutorialUnwrap6.gif (24517 bytes)

 

Use the Button-Toolbar-SampleTool.gif (934 bytes) sample tool from the Edit Toolbar to sample the body color. There are a number of shades of yellow, so we want to ensure that we have the right one.

Use the Button-Toolbar-Paint.gif (941 bytes) Face Painting Tool from the Edit Toolbar to repaint the areas accidentally painted green. There should be a relatively smooth edge between green and yellow. But since we are painting faces, the line between green and yellow will never be entirely smooth. Just make sure that green is contiguous.

 

TutorialUnwrap7.gif (24533 bytes)

 

Use the Button-Toolbar-FaceGroupSelectionTool.gif (911 bytes) Face Group Selection Tool to select the faces that make up the diaper. Paint them white. This will be the only part of the model that will not be texture wrapped.

Notice the over-run of paint again. If the creator of the model had kept the diaper as a separate object, this would have been much simpler. Since they have been merged into a single object, it is necessary to do a little bit of clean up.

 

TutorialUnwrap8.gif (21855 bytes)

 

Use the Button-Toolbar-Paint.gif (941 bytes) Face Painting Tool to repaint the areas of the body accidentally painted white.

 

TutorialUnwrap9.gif (28319 bytes)

 

Paint the tops of each hand and each foot a unique color.

Ensure that you are very careful to paint only the top part of each hand. To see a more detailed view of properly masked hands click here.

We have now completed the color masking of our object.

 

TutorialUnwrap10.gif (19920 bytes)

 

Click Button-Toolbar-SelectFace.gif (906 bytes) to select the Point and Face Selection Tool. It is located on the Edit Toolbar.

Alt-Ctrl click anywhere on the yellow part of the body. This will select all faces that are yellow.

 

TutorialUnwrap11.gif (23254 bytes)

 

Create a skin-tone texture using your Paint program. Select it using the Material Palette. Click Button-WrapSphere.gif (917 bytes) on the Material Palette to select a spherical wrap.

Note that even though this skin tone is a continuos color, it must be a texture. Textures and colors do not render exactly the same, so if there is a mix of colors and textures it will be obvious in the model.

Fill the selection with this texture using the Button-Toolbar-FillTool.gif (941 bytes) Material Fill Operation from the Operation Panel.

 

TutorialUnwrap12.gif (23809 bytes)

 

We will now create a bitmap of the baby's face that we can paint.

To use the Unwrap operation, the area of the object to be unwrapped must be facing towards you when looking at the object in a Front Orthographic view. Ensure that this is the case. If it isn't, rotate the object so it faces you.

Click Button-WrapCylinder.gif (919 bytes) on the Material Palette to select a cylindrical wrap. This is usually the best wrap method for character faces. You may find that with some character faces a spherical wrap or even a flat wrap produces the best result. The best method is to try each wrap type until the Unwrap Operation produces a bitmap you are happy with.

Click Button-Toolbar-SelectFace.gif (906 bytes) again to select the Point and Face Selection Tool. Alt-Ctrl click anywhere on the green part of the face to select it.

Click Operation-Unwrap.gif (914 bytes) on the Operation Panel to open the Unwrap Operation.

Select a texture size of 512x512 and click OK. Save the file somewhere where you won't lose it.

 

TutorialUnwrap13.gif (21444 bytes)

 

In your Paint program, open the texture you created, and change all of the grey areas to the exact color that you used in your previous skin tone texture.

Also, change all of the white areas to a color that will not be part of the final texture. I chose yellow for this example.
TutorialUnwrap14.gif (33477 bytes)

 

Here I have painted in the eyes and lips of the texture.
TutorialUnwrap15.gif (27133 bytes)

 

Select this texture you created using the Material Palette and apply it to the object using the Button-Toolbar-FillTool.gif (941 bytes) Material Fill Operation. If you deselected the the green mask, you will first have to re-select it by Alt-Ctrl clicking.

Don't worry about any creasing between the face texture and body texture. This will be resolved in the final step.

Notice that the areas near the ears have a lot of overlap of faces. It would not be appropriate to try to paint areas such as this because the result would be poor. If you were to want to paint the ears, you would have to create separate masks and bitmaps for them or reduce the size of the color mask around the ears.

 

TutorialUnwrap16.gif (27133 bytes)

 

It is actually possible to see how changes you make to the texture affect the model while you are modeling. As you make a change to the texture in your Paint program, simply save it and reload the model to see what the effect has been. It isn't always obvious what point in the texture is what point on the model so some trial and error may be necessary.

I have now filled all of the yellow lines with skin tone, and added some blush to the cheeks.

 

TutorialUnwrap17.gif (21492 bytes)

 

We will now repeat this process for the other masked areas.

Remember that in order to use the Unwrap Operation, the area to be unwrapped must face the front.

Rotate the model as shown so that the area to be wrapped faces the front.
TutorialUnwrap18.gif (25086 bytes)

 

Repeat the process of creating a bitmap, but this time use a Button-WrapFlat.gif (920 bytes) Flat Wrap.

 

TutorialUnwrap19.gif (15083 bytes)

 

Paint fingernails on this texture and apply it to the object.

Repeat this process for the other hand and the feet.
TutorialUnwrap20.gif (26341 bytes)

 

Apply the Operation-Crease.gif (514 bytes) Crease Operation and adjust the slider to the far left so that there is no creasing. This will correct any seams that appeared when the textures were applied.

We now have our finished model.
TutorialUnwrap21.gif (22530 bytes)