Creating Flow Maps on Multiple Objects

It may often be necessary to create flow maps for different objects in a project, effectively separating the vector data into more than one channel. Following the steps below prevents the vector markers from appearing on multiple objects when attempting to focus on creating flow maps on only a single object.

Set up a basic channel on objects that do not need flow maps, in the Channels palette, by either:

• right-clicking on the palette and selecting Add Channel from the dropdown menu, or

• clicking on the add channel button.

Mari displays an Add Channel dialog box.

Note: Ensure that you have the correct object(s) selected before you begin, to avoid creating any unnecessary channels on the wrong object.

Create a channel, called "gray" or similar, and set the Color to mid-gray (RGB: 0.5, 0.5, 0.5). Create the channel for only the selected object, for this example, called Object A.

Using the gray Quick Channel can simplify the process, but if you have multiple quick channels in the
Channels palette, make sure you rename it to avoid any confusion when setting up the shader in the instructions below.

Tip: Create the channel or quick channel with a 256x256 Size to avoid taking up unnecessary space.

Set up vector default shaders by navigating to Python > Examples > Setup Vector Brush or by clicking the

icon in the Vector Painting toolbar.

The script creates two default shaders, and associated channels and layers in each of the Shaders, Channels, and Layers palettes. These allow you to quickly set up the shaders for vector painting and flow maps.

With Object A still selected, in the Shaders palette, select the Vector (World Space) shader that was created by the vector default shader script.

The Diffuse Color shader component should already be filled in.

Click on the dropdown menu for the Vector shader component and select the "gray" channel you created in the Channels palette.

The Vector shader component, when set up this way, blocks out the vector inspector markers on objects you don’t want to create a flow map for.

Lock Object A by clicking on the padlock icon

in the Objects palette. Due to the fact that vector paint can still be applied to the object - even if vector inspector directional markers aren’t shown - this ensures you don’t paint over your textures.

Select a second object for which you want to create a flow map. For this example, the second object is called Object B. Create default vector shaders, channels, and layers using the script in step three above.

The Vector (Paint) channel is already set to the Vector shader component in the Vector (World Space) and Vector (Screen Space) shaders. This allows you to see the flow map channel where the vector markers are present, without affecting other objects.

If you don’t already have them activated, turn on the vector painting directional markers by clicking on the

icon in the Vector Painting toolbar before painting your flow maps.

If you paint on the model now, paint is applied to all unlocked objects. However, only objects with the Vector (Paint) channel listed in the shader’s Vector shader component field show the vector inspector markers.

Note: For more information on shaders and shader components, please see Shaders.