Projectionist is a wonderful handy Nuke module with scripts for creating projection setups. Currently three commands are provided:
- Create a projector from this camera
- Create projection alley from this camera
- Convert this camera to nodal with dolly axis
For both to work you need to select a camera. The camera needs to be unlinked from it's FBX file if you use that.
This will create a copy of your current camera, freeze it at the frame you are in the script,
and optionally create you a Project3D and a FrameHold you can plug your footage into. This camera is linked to the original camera
and has a knob which you can use to timewarp the camera (when you animate the at knob it will sample the source camera from the provided frame).
This is something you have to do alot so this setup is automated to the top.
This will take your camera across a framerange, and create a number of projecting cameras frozen at frames in the framerange. From each one of these it will create a frame hold node and a project3d shader, and the shaders will all be combined. So the output of this command is a group that has all the projection cameras embedded into it, as well as shaders - it's output is also a shader. Connect a premultiplied plate into the input of the group, and it's output is a projection shader with multiple frames layered on top of each other. Layering uses alpha masking, so if you roto out your talent you will get a cleanplate in the shader space.
It's also majorly useful for extracting textures from big camera moves - like flyovers, aerial shots or drive shots.
The layering setting defines the stacking order of the projected patches. Basically, you should aim to always have the highest-resolution patches on top of the rest. Since the textures are going to be layered along the framerange, there is a choice to be made in terms of layering.
- back to front - if your camera flies toward the subject or zooms in. The frames with higher numbers will end up on top.
- front to back - if your camera flies away from the subject or zooms out. Frames at the beginning of the sequence will end up on top.
A camera zooming into a window of a skyscraper should definitely layer back to front.
The projection alley technique is especially handy for matte-painting base extraction. For instance, a long zoom/pan can easily give you this cool texture as a result (you can then bake it using a UV render, or register it with a camera to get a flat projection):
This will extract the position animation of your camera into a separate Axis node (your "dolly"). The camera will be then repositioned to the origin of the scene and parented to the dolly axis - so that you have a moving camera mount that does not rotate, and under it the camera itself. Having done that you can easily attach your nodal elements (environment maps, lights and cards) to the axis that drives the camera and the elements will be properly positioned yet flying together with the camera mount.
Copy the directory somewhere, for example into your $HOME/.nuke. Then import the module into your Nuke's menu.py, like this:
nuke.pluginAddPath('/Users/fred/.nuke/projectionist')
Note that projectionist does NOT contain any gizmos, so your script will not be polluted - it just helps you create things.
Created by Julik Tarkhanov [email protected] in Amsterdam, 2011.