Using External Tools

Several external tools can be valuable when you create material textures. These tools can include an image-editing program like Photoshop, a digital camera or camcorder, and a scanner. With these tools, you can create or capture images that can be applied as maps to a material using the map channels.

After the image is created or captured, you can apply it to a material by clicking a map shortcut button or by selecting a map in the Maps rollout. This opens the Material/Map Browser, where you can select the Bitmap map type and load the image file from the file dialog box that appears.

Creating material textures using Photoshop

When you begin creating texture images, Photoshop becomes your best friend. Using Photoshop's filters enables you to quickly create a huge variety of textures that add life and realism to your textures.

Table 21.1 is a recipe book of several common textures that you can create in Photoshop. The table provides only a quick sampling of some simple textures. Many other features and effects are possible with Photoshop.

Table 21.1: Photoshop Texture Recipes
Open table as spreadsheet

Texture	Technique	Create in Photoshop	Apply in Max as
	Faded color	Decrease the image saturation value (Image Adjustments Hue/Saturation) by 20 to 30%.	Diffuse map
	Surface scratches	Apply the Chalk & Charcoal filter (Filter Sketch Chalk & Charcoal) with a Stroke Pressure of 2, to a blank white image, and then apply the Film Grain (Filter Artistic Film Grain) filter with maximum Grain and Intensity.	Bump map
	Adding stains to fabric	Use the Dodge and Burn tools to add stains to a fabric bitmap.	Diffuse map
	Surface relief texture	Apply Dark Strokes filter (Filter Brush Strokes Dark Strokes) to a texture bitmap, and save the image as a separate bump image.	Diffuse map (original texture), Bump map (Dark Strokes version)
	Planar hair	Apply the Fibers filter (Filter Render Fibers).	Diffuse, Bump, and Specular maps
	Clouds or fog background	Apply the Clouds filter (Filter Render Clouds).	Diffuse map
	Nebula or plasma cloud	Apply the Difference Clouds filter (Filter Render Difference Clouds). Then switch black and white color positions, and apply the Difference Clouds filter again.	Diffuse map
	Rock wall	Apply the Clouds filter (Filter Render Clouds), and then apply the Bas Relief (Filter Sketch Bas Relief) filter.	Diffuse and Bump maps
	Burlap sack	Apply the Add Noise filter (Filter Noise Add Noise), followed by the Texturizer filter (Filter Texture Texturizer) with the Burlap setting.	Diffuse and Bump maps
	Tile floor	Apply the Add Noise filter (Filter Noise Add Noise), followed by the Stained Glass filter (Filter Texture Stained Glass).	Diffuse map
	Brushed metal	Apply the Add Noise filter (Filter Noise Add Noise), followed by the Angled Strokes filter (Filter Brush Strokes Angled Strokes).	Diffuse and Bump maps
	Frosted glass	Apply the Clouds filter (Filter Render Clouds), and then apply the Glass (Filter Distort Glass) filter and select the Frosted option.	Diffuse map
	Pumice stone	Apply the Add Noise filter (Filter Noise Add Noise), followed by the Chalk & Charcoal filter (Filter Sketch Chalk & Charcoal).	Diffuse and Bump maps
	Planet islands	Apply the Difference Clouds filter (Filter Render Difference Clouds), and then apply the Note Paper (Filter Sketch Note Paper) filter.	Diffuse and Shininess maps
	Netting	Apply the Mosaic Tiles filter (Filter Texture Mosaic Tiles), followed by the Stamp (Filter Sketch Stamp) filter.	Diffuse and Opacity maps
	Leopard skin	Apply the Grain filter (Filter Texture Grain) with the Clumped option, followed by the Poster Edges (Filter Artistic Poster Edges) filter applied twice.	Diffuse and Opacity maps

Capturing digital images

Digital cameras and camcorders are inexpensive enough that they really are a necessary item when creating material textures. Although Photoshop can be used to create many unique and interesting textures, a digital image of riverbed stones is much more realistic than anything that can be created with Photoshop. The world is full of interesting textures that can be used in creating images.

Avoiding specular highlights

Nothing can ruin a good texture taken with a digital camera faster than the camera's flash. Taking a picture of a highly reflective surface like the surface of a table can reflect back to the camera, thereby ruining the texture.

You can counter this in several ways. One is to block the flash and make sure that you have enough ambient light to capture the texture. Taking pictures outside can help with this because they don't need the flash. Another technique is to take the image at an angle, but this might skew the texture. A third technique is to take the image and then crop away the unwanted highlights.

Adjusting brightness

Digital images that are taken with a digital camera are typically pre-lit, meaning that they already have a light source lighting them. When these pre-lit images are added to a Max scene that includes lights, the image gets a double dose of light that typically washes out the images.

You can remedy this problem by adjusting the brightness of the image prior to loading it into Max. For images taken in normal indoor light, you'll want to decrease the brightness value by 10 to 20 percent. For outdoor scenes in full sunlight, you may want to decrease the brightness even more.

You can find the Brightness/Contrast control in Photoshop in the Image Adjustments Brightness/ Contrast menu.

Scanning images

In addition to taking digital images with a digital camera, you can scan images from other sources. For example, the maple leaf that was modeled using patches in Chapter 17 was scanned from a real leaf found in my yard.

Caution 

Most magazine and book images are copyrighted and cannot be scanned and used without permission.

Tutorial: Creating a fishing net

Some modeling tasks can be solved more easily with a material than with geometry changes. A fishing net is a good example. Using geometry to create the holes in the net would be tricky, but a simple Opacity map makes this complex modeling task easy.

To create a fishing net, follow these steps:

1. Before working in Max, create the needed texture in Photoshop. In Photoshop, select File New, enter the dimensions of 512 pixels × 512 pixels in the New dialog box, and click OK to create a new image file.

2. Select the Filter Texture Mosaic Tiles menu command to apply the Mosaic Tiles filter. Set the Tile Size to 30 and the Grout Width to 3, and click the OK button. Then select the Filter Sketch Stamp menu command to apply the Stamp filter with a Light/Dark Balance value of 49 and a Smooth value of 50.

3. Choose File Save As, and save the file as  Netting.tif.

   A copy of this file is available in the Chap 21 directory on the DVD.

4. Open the  Fish net.max file from the Chap 21 directory on the DVD.

   This file includes a fishing net model created by stretching half a sphere with the Shell modifier applied.

5. Select the Rendering Material Editor menu command (or press the M key) to open the Material Editor, and select the first sample slot. Name the material net.

6. Click the map shortcut to the right of the Opacity value in the Blinn Basic Parameters rollout, and double-click the Bitmap map type. This opens a file dialog box where you can select the netting texture. Then drag the material from its sample slot to the net object in the viewports.

7. If you were to render the viewport, the net would look rather funny because the black lines are transparent instead of the white spaces. To fix this, open the Output rollout and enable the Invert option. This inverts the texture image.

Note 

Although you can enable the Show Map in Viewport button in the Material Editor, the transparency is not displayed until you render the scene.

Figure 21.15 shows the rendered net.

Figure 21.15: A fishing net completed easily with the net texture applied as an Opacity map