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Creating Render Material in AutoCAD – 2

7 Comments Mar-21-2007 | Posted by Erhan Toker | Printable Version | Level |

AutoCAD 2007 and higher versions

In second part of our article series, we will explain how to create a TEXTURED material. A typical textured material is shown in Fig. 1.
 

Fig. 1

Texture files can be created in JPG, TIFF, TGA, BMP or PNG formats. However, most economical one regarding files size is JPG. There are some certain points that you should take into account while creating texture pictures:

1. Texture should be able to repeat itself.
2. Size of texture picture as of number of pixels.
3. Color calibration of our own screen.

1) Texture repetition : The most important property of textures is that they can repeat themselves over the surface that they cover. Otherwise, if we cover a relatively large area with a small texture, then we obtain a blurry and undesirable picture. This can be explained best by windows wallpaper example. Even though some of the wallpapers are two percent of the whole screen, by using TILE option we can see that our desktop is covered with very nice textures. Preparing such a texture needs a lot of efforts. Especially when four edges coincide, texture lines must follow each other (Fig. 2).
 

Fig. 2

Texture picture shown in Fig. 2 is made up of combination of two of pictures that is shown in Fig. 1 side by side. Even though it is a perfect example for texture continuity, this is not enough for all only by itself. It is also required for color saturation and brightness level at the edges to be equal, so that there will not be any waving effect.

2) Size of Texture picture as number of pixels: If the texture picture is specially prepared for one project, then in order to obtain the best results, it should have the same size with the size seen in render (Fig. 3).

Fig. 3

In Fig. 3, ideal size for the texture picture is 200×120 pixels. However, texture materials are generally prepared for general purposes and as I described in 1. item, they should be repetitive. For a repeatable texture, approximately 200×200 pixel size is ideal.

3) Monitor color calibration : Most of you are not using professional monitors. For this reason, colors that you see in you monitor may not be real colors. If you add the color mistakes due to your scanner, textures that you have prepared may not look the same as you desire in other computers. For this aspect, you should pay attention to keep color settings of your monitor and scanner as good as possible and as close as possible to real colors.

As our texture picture is ready, than we can immediately use it inside a material definition. Let’s create a new material from Material control panel with name of “CHERRY”. After this, select JPG file (in my example FFE2.jpg ) that we prepare as material shown in Fig. 4, as ‘Texture Map’.

Fig. 4

After making the selection by using ‘Select…’ button, you will see that name of the button is changed as the texture file name. There is a texture setting just on the right side of the button. By using this icon, we can access settings window by using this icon (Fig. 5).

Fig. 5

There are the settings for repetition and scaling in ‘Bitmap Scale’ group. If your texture is prepared for a single drawing ( painting, wallpaper etc. ), then you can use ‘Fit to object’ option. Size of texture picture as of pixel dimensions is important at this stage. You should take into consideration the area of surface that will be covered. Beside this selection, you can also set the number of repetitions in U and V ( X, Y ) directions. By this way, you can have the texture picture to be placed by NxN times over the relevant surface.

Fig. 6

Our other option is to scale our texture. We must use ‘Tiled’ ( repeated ) option while scaling. You should pay attention for scaling unit and  drawing unit to be the same. After these settings, values that we write in width and height areas will determine reparation spacings. For example, a repetition is foreseen with 45 cm intervals.

Offset and Rotation : On the lowest part of screen (Fig. 7), you can set how much the texture will be offset in U and V directions and how many degrees it will be rotated according to the surface.

Fig. 7

After definition is completed, you can try your material by assigning to various surfaces. In third and last article of this series, I will explain about MAPPING ( layout alignment ) topic.

Since then, take care.

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