Volume Object Paint Mode

The proposal is to allow Blender users to edit and create their own <b>shapes of volume</b> with <b>varying density, temprature</b>, etc. by directly painting, editing volume layers in 3D using brushes and 3D textures, instead of making a mesh, simulating or doing shader math.

This allows for a natural extension and adding possibilities to recently added Volume Objects.

• Voxel resolution could be strict and set within volume object parameters (from specifying or imporing).
• Drawing plane could be the closest point at mouse cursor or the position of the 3d cursor

Possible use cases:

• Tweaking, editing and modifying existing .VDB files, Volume objects' layers
• Adding artisticly-directed fog/volume effects to envirovments and objects

(i.e rocket trails, corridor fog, helicopter dust, tube smoke)

• Creating volumes from scratch without using any other object or custom shaders
• Making volume shapes with varying density that could not be easily achieved by using meshes, simulation or shaders
• Converting complex volume shapes to mesh -> using Boolean modifier to cut geometry within a specific 3d volume