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Creating Render Material in AutoCAD – 3: Mapping

8 Comments Mar-22-2007 | Posted by Erhan Toker | Printable Version | Level |

AutoCAD 2007 and higher versions

When a texture material is assigned to a surface or a solid entity, then according to the shape of the entity, AutoCAD automatically covers it with that texture material. However, thing may not work out as we expect all the times and AutoCAD may make some mistakes; or we may have some special demands.

When we discussed about material definitions, we described about tile property. This property is distributed to all of the surfaces equally in standard applications. When mapping is applied to any material, mapping area will be the area that is taken as basis for material. Accordingly, if the mapping area is larger than the surface to be covered, only part of the mapping area that covers the entity will be used; otherwise, whole mapping area will be used so that it will be repeated. When expressions are explained in words it may be a little confusing. So, it is better explained by an example like covering a cylinder, cube or sphere by using a typical woodwork ( with thick, clear veins). The way woodworks look is independent from shape, when they are massive. However, if we cover these entities, then the texture will take the shape of them. That’s what mapping is. Now, let’s continue with an example. There are 4 different kinds of mapping in AutoCAD:

1. Plannar mapping
2. Box mapping
3. Spherical mapping
4. Cylindirical mapping

It is obvious what they do, when you look at their names. Now, let’s examine them closely one by one:

1. Plannar Mapping :

Fig. 1

As it can be understood from its name, it is assigned to planar surfaces. It can also be assigned to other forms in order to get massive effect. Mapping menu is included inside the render menu ( Fig. 2).

Fig. 2

Due to the fact that mapping is applied to entities, you will have to select an entity and it will start working on an appropriate mapping as soon as you select one ( Fig. 3).

Fig. 3

Blue triangles that are on the corners are used for changing dimensions and shapes. It is similar to STRETCH command. Green, red and blue stripes ( blue stripe is seen in drawing as line ) are used for rotating axis. When we take a look at command line in this editing mode, then we can see mapping sub-menu:

Accept the mapping or [Move/ Rotate/ reseT/ sWitch mapping mode]:

By pressing enter, you can accept settings. MOVE and ROTATE does the work that we already know. We can use MOVE option if we don’t want to start from the corner of the texture; it is especially useful for paving floor tiles. RESET returns all of the values to their default values. And, ‘sWitch to mapping mode’ is used for accessing one upper menu:

Select an option [Box/ Planar/ Spherical/ Cylindrical/ copY mapping to/ Reset mapping]:

This is actually the first menu ( MATERIALMAP ) that comes up when you first enter the command. You can copy mapping settings of one entity to another by using ‘copY mapping to’ or you can delete a mapping by using ‘Reset’.

2. Box Mapping :

Fig. 4

In Fig. 4, you can see that box mapping is assigned to a cube shaped entity. Similarly as before, the blue triangle and colored stripes are waiting for to be used. If spherical mapping is assigned to the same entity, then it will look like that is shown in Fig. 5.

Fig. 5

In order for you to see the difference, I am giving this example.

3. Spherical Mapping:

Fig. 6

Modifications that can be made by using spherical mapping are only limited to ROTATE. This command defines the polar of cube. In figure, you can see the state of texture material during and after editing.

4. Cylindirical mapping:

Fig. 7

In Fig. 7, entity that is on the left side is shown by using cylindrical mapping and the one on the right is shown by using planar mapping. As it can be seen on the entity that is on right side in figure, texture is being rendered along the cylinder.

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