The Complete Guide to Blender Graphics
Dynamic Paint

Introduction


Dynamic paint is modifier and physics system that can create vertex colors, image sequences or displacement on object surfaces. This makes many effects possible that were previously difficult to achieve, for example footsteps in the snow, raindrops that make the ground wet, paint that sticks to walls, or objects that gradually freeze.

The dynamic paint tool is a fantastic application and there are many tutorials on the internet which show how to apply some varied and fantastic effects. As with many aspects of Blender it may prove daunting to a new enthusiast without a very basic introduction its application through the graphical user interface.


The Basics

The basic concept is that one object is used to paint material color or deform the surface of another object. We will begin by painting a material color on to the surface of a “Plane” object by using a “UV Sphere” object. The “Plane” (The object being painted)is called the “Canvas” while the sphere (The object applying the paint) is the “Brush”.


The Canvas

In the default 3D window, delete the default “Cube” and add a “UV Sphere”. Scale the sphere up and subdivide six or seven times to produce a reasonable number of vertices. The greater the number of vertices the smoother the edges of the painting will be.

Add a “Material Color” to the plane (Darkish Blue). In the “Materials” buttons, “Options” tab check “Vertex Color Paint” to enable rendering of the color to be painted on the “Canvas”.



In the “Properties” window, “Physics” buttons, click on “Dynamic Paint”  to enable physics.

By default, in the “Dynamic Paint” tab “Canvas” is selected (highlighted in blue). Click on “Add Canvas” to display the physics settings tabs.

Note that the “Format” is “Vertex” which means that :Material” will be applied to the vertices of the “Canvas” (the plane).

Check “Anti-aliasing” to employ 5x multisampling to smooth the paint edges.

In the “Dynamic Paint Advanced” tab note the “Surface Type” is “Paint”. There is a selection menu here with four options: Paint, Displace, Weight and Waves. These will be explained later but for the time being we will use the “Paint” option.


In the “Dynamic Paint Output” tab click the cross at the end of the “Paintmap” layer bar. This assigns a layer and enables rendering. The default name of the render layer is shown as “dp_paintmap”.


Note: without assigning the “Paintmap” layer or activating “Vertex Color Paint” in the “Materials” buttons the paint applied to the “Canvas” will not render to an image.


Deselect the plane.


Dynamic Paint Advanced

The Brush


Add a “UV Sphere” object to the scene and position it as shown in the diagram to one side of the plane. Animate the sphere to move to the opposite side of the plane in 50 frames.


Note: “Dynamic Paint” requires the “Brush” to be animated to move over the surface of the “Canvas”.


With the sphere selected, add a “Material” color (Redish Brown). Go to the “Properties” window, “Physics” buttons and again click on “Dynamic Paint” to activate physics. “Dynamic Paint” type “Canvas” is active by default. Change this to “Brush” and click “Add Brush”.


In the “Dynamic Paint” tab note the color selection bar just below “Use object material”. By default the material color in the bar is a blue color similar to that applied to the plane. At this point the paint color options are to use the color displayed in the color bar or to use the “Material” color that has been applied to the “Brush”.


To demonstrate click on the color bar and select a bright green color. Play the animation in the “Timeline” window. A strip of green is applied to the surface of the plane. Change the color in the color bar and replay the animation. The new color is applied. In the “Dynamic Paint” tab check “Use object material”. Click on the little sphere icon which displays in the color bar and select the color of the sphere from the menu. Replay the animation.


Canvas Surface Type Options


Make sure the “Canvas” is selected. Revisit the “Physics” buttons, “Dynamic Paint Advanced” tab. In the “Surface Type” selection menu select the different options in turn and play the animation. Displace, displaces the vertices of the surface, Weight applies a “Weight Paint” which assigns the effected vertices for “Armature” animations and Waves creates waves (ripple effect) on the surface of the canvas.

Paint Source


The “Brush” has several options for paint application which are found in the “Physics” buttons, “Dynamic Paint Source” tab. By selecting each option in turn and playing the animation the different effects can be observed. Make particular note of the “Particles” option. This option can only be used when a “Particle System” has been applied to the “Brush” and note that it will not work when “Use object material” is checked.



Paint Source Particle System


To demonstrate the “Paint Source: Particle System” option relocate and animate the “Brush” (UV Sphere) above the “Canvas”. Apply a “Particle System” to the sphere. The “Emitter” type with the default settings will serve for the demonstration. In the “Physics” buttons, “Dynamic Paint Source” tab select “Paint Source: Particle System”. In the “Dynamic Paint” tab make sure “Use object material” is NOT checked. Select a material color in the color bar different to that of the “Canvas” and the “Brush”.


In the “Dynamic Paint Source” tab click on the bar just below “Paint Source” and select the particle system yhat has been applied. With the default settings this is simply named “ParticleSystem”.

Play the animation to see paint applied to the canvas as particles come in contact with it. This is if you have surface type “Paint” selected. If you have surface type “Waves” selected you will see a water droplet effect.


Note: If you have inadvertently selected “Use object material” in the “Brush – Dynamic Paint” tab, Blender will crash when you attempt to enter the particle system.


Summary


This has been a very basic introduction to “Dynamic Paint”. There are many setting that you will have to experiment with to become proficient and there are many tutorials to be studied which will show the fantastic effects that can be created.


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In each case when selecting one of the options the button controls change to provide adjustments to the different effects.


Note: With “Surface Type – Waves” selected for the “Canvas” there are additional controls in the “Brush” physics buttons “Dynamic Paint Waves” tab.