Inventor Mapping Tips & Tricks
This is a simple 96x96 directional test pattern used to determine texture mapping orientation in Inventor. This is the image size recommended in Inventor's help file. This is another case where size does matter. 96x96 pixle test image.
These are copies of the 96x96 image enlarged to 128x128, 256x256, and 512x512 bitmaps. You can see some colorshifting in these and other images on this page due to their being converted to the JPG image format for display in your web browser. 128x128 pixle test image.
Fitting Images to Surfaces
This is a test item built with Inventor R7. It is 400 mm long, 200 mm wide, and 140 mm high. It is just a display model built for this mapping example page, and represents a generic cast alloy cover as might be used in many industries. The first image is the cover mapped with the 96x96 directional image applied with a texture scale factor of 100%. Image of casting mapped with 96x96 pixle test image
This test image has had the 128x128 directional texture applied at 100%. If you'll note the lower right hand sides of these images, the edges of the mapped directional textures don't align very well. This is due to the way Inventor applies the texture maps to the model. This is built into Inventor and is not user adjustable. Image of casting mapped with 128x128 pixle test image.
The 256x256 texture image in this example show how mapping alignment allows more haphazard patterns. Image maps with specific and repeating shapes will not appear realistic with this amount of distortion. Although the shape of the model might be modified to display certain textures more realistically, more accurate models may be far more valuable than pretty ones. It can be hard to find a compromise between product design and product engineering. Image of casting mapped with 256x256 pixle test image.
This 512x512 directional texture image would be more appropriate on a larger curved or flat surface. The tight short sides and relatively tight radii allow only small portions of the mapped image to be used. Image of casting mapped with 512x512 pixle test image.
This is a closer view of the 128x128 directional mapped image. Note how some images are upside down, while others are turned sideways. You have no mapping options which would align texture images or control their direction. This must be performed within your textures and can require a great deal of experimentation.
Success isn't guaranteed.
Close up image of casting mapped with 128x128 pixle test image.
This is the same view using Inventor's Zebra Stripe face analysis tool. It can be used to see how faces and edges match up with their neighbors. You'll note that even this built-in function has display problems in specific areas. Close up image of casting mapped with Inventor's Zebra Stripe analysis tool.
This view is mapped with a 128x128 bitmap representing red wrinkle paint. Note how the upside down, sideways, or magnified portions don't stand out when using such a busy pattern. Inventor's color/texture dialog box is used to control lighting and highlighting of an internally colored bitmap such as this. While grayscale bitmaps are usually preferable over predetermined colors, adding red lighting to a grayscale version of this texture results in a muted and muddy image. Close up image of casting mapped with a wrinkle red paint texture.
This is a screenshot of the WRINKLE_RED.BMP texture used in the above example. A close-up shows the relatively simple pattern and its use of only three colors. This texture was made by modifying the PLASTIC_10.BMP texture which is installed with Inventor. Image of Wrinkle Red paint texture.  This is a close-up image of red wrinkle paint. It contains only three colors.
This is a bad trick that Inventor does as it applies specifically designed directional bitmaps. Notice that the area outlined in red is upside down and magnified. A texture map like this engine turning works really well on singular flat or slightly curved faces.
Real engine turning is the same way. Engine turning real curved or complex features eats up long hours with under whelming results.
For those unfamiliar with engine turning, it is accomplished with a spinning abrasive applied in offset rows which forms the unique pattern. Generally a rod made of Craytex (abrasive rubber polishing tool), or a short stiff brush packed with polishing paste, or even a pencil eraser is spun in a drill press or similar apparatus, and the spinning abrasive is pressed into the work surface at regular distances and for a repeatable amount of time. Properly applied it is nothing short of an art form.
Image of failed engine turned texture.
This bitmap was made by rendering the end of a pointed silver colored cylinder in AutoCAD. The saved single instance bitmap was imported into Corel PhotoPaint, it's background turned transparent, and the resulting image was imported into a new PhotoPaint file. The single image was copied and positioned into several rows and columns. Notice that the centers of each turning aren't perfectly aligned. This gives the visual effect of excellent hand craftsmanship instead of a perfect machine made pattern. Image of engine turned grayscale bitmap.
Texture Map Color Control
This is an example of using ambient light to control color. The grayscale bitmap used in this example replicates Hammertone paint. This 1.4MB bitmap is 1024x1024 and needs to be trimmed considerably before being released to the public. Bitmaps of this size can rob Inventor of valuable resources on even the most powerful workstations. The results are stunning and are extremely hard to distinguish from actual Hammertone paint, but the overhead is too great. Image of casting mapped with Hammertone paint.
This is a small portion of the HAMMERTONE.BMP image. It began life as an image of slate building material. Heavily modified, it is now on it's way to a new life. Image of hammertone texture map (reduced size).
These are the color settings used to bring Hammertone to reality. Note that it's color is set with the Ambient light setting. Any of the commercially available Hammertones can be duplicated with this single setting. Image of Inventor color control dialog showing color selections for Hammertone texture map.
This image is of the basic casting with a bumpmapped texture. It doesn't look like much at this scale, just sort of a muted gray finish. Image of casting mapped with grayscale bitmap.
This is the bumpmap used above. Notice how sharply defined the dark/light areas appear. It looks a lot like rough silver sandpaper. Image of sandcast grayscale bitmap.
These simple and muted colors add a bit of a natural daylight effect to the model. A little sky, a little sunlight, some british highlights. Nothing all that special. Image of Inventor color control dialog showing color selections for sand cast texture map.
This is as close to photorealistic as you'll see with current computer technology. The faux-bumpmap depth of the surface texture and the natural light color highlighting combine to create the illusion of slightly aged sand cast aluminum. This is far greater detail than that required for motion picture CGI texture maps. This simple and basic texture has surprised many people in many industries. Top view of sandcast texture.
This is a tiny 72x72 grayscale bitmap that replicates a carbon fiber woven composite material. Image of carbon fiber texture bitmap.
The color settings set the shadows and highlights. Nothing very special is required. Image of Inventor color control dialog showing color selections for carbon fiber texture map.
This carbon fiber texture thrives in the Inventor mapping environment. Where confused mapping caused problems with other textures it greatly enhances the realistic appearance of directional ply composite materials. Turning up the shininess control would make this structure appear more like a wet laid-up composite as it would contain a higher percentage of resin, although that's not really desirable. Image of casting mapped with carbon fiber bitmap.
This is an example of a texture map work in progress. The idea is to duplicate the effect of copper/gold/silver veined powder paints in general use. Image of veined powder paint texture bitmap.
This is how the current Copper Vein texture map appears on a simple surface. This is a bad texture. It's so dark that none of the surface details are visible. A texture based black hole. Failed image of copper vein powder paint.