cmivfx _nuke facial replacement techniques
English | Size: 493 MB
This new video discussed several areas of Visual Effects in regards to doing facial / muzzle replacement techniques while in a compositing environment. We will show you how to stay in Nuke for the entire voyage of capturing the motion and turning it into a monstrous transformation.
Start off by separating the talent from the green screen background, then key in sections of the head, body and core to preserve as much detail and data as possible. Utilizing the Nuke camera tracker begin the projection and mesh alignment stages before moving into painting and texturing the shot. Learn how to add in additional alterations such as grid and spline warp, muzzle flashes and displacements. The final result will be amazing and these techniques will transfer to many other projects.
The talent was shot on a green screen and the first aspect of this video will be to separate him from the green background.
Part I: Head
The need to preserve as much detail as possible is necessary, learn how to key the hair and head separately from the body. Remove unwanted areas with a Bezier and then use a key light to concentrate on creating a fine edge.
Part II: Body
The body is the second area of interest. Again, key out this area independently from the rest, in order to not get a hard edge the exception of holes in the matte will be necessary.
Part III: Core
This matte merges our head and our body matte. Begin to close any of the unwanted holes that remain in the shot and this process will create a nice solid matte while maintaining the edge details of the other matte’s. Once completed the process of compositing the shot into the BG plate can begin.
Using Nuke’s camera tracker to track the forehead the moment of the camera relative to the head can be derived. Using this camera as a projector, project the face onto generic head geometry.
Align the head mesh so that the features of the projected face line up with the nose, eyes and mouth of the geometry. This gives a textured 3D head model which can be render out, creating a texture (UV map) to modify it.
Writing out a single frame of the faces texture gives the option to do some paint work on it. Utilizing Photoshop add a scarred or burned area to the face, by using very basic paint tools and layering images to use as textures on top.
Part IV: Texturing
Load the painted version back into Nuke and now the ability to re-texture the mesh is ready since it is already in the proper UV layout. Also load in an alpha of the paint work to define the area needed to use further down in the script.
The grid warp can be a useful tool when warping from one face to another. Here cover the basic functions from setting up the source grid and animating the destination grid. Yet when it comes to connecting trackers to the grid the spline tool seems more adequate for the task.
The spline warp is very similar to the grid warp. Being able to draw a transformation area is not its only benefit. Its ability for single points to be connected to tracking points can be very useful.
Adding some muzzle flashes to a rifle is always fun, even better if there is a way to use the brightness of the flashes to drive the intensity of the lights in the 3d scene. The flickering of the lights becomes even nicer when adding a Phong shader to the texture.
To make the painted features of the face stand out even more, simply displace the geometry. Also altering the animation of the head and the painted area would still stay in place.
About The Author
Derk started his career as a graphic designer for vintage merchandising products. Not being solely interested in pub signs, he shifted his focus to moving image and visual effects while studying visual communication in Aachen (Germany) and Birmingham. For the past four years he has delivered creative solutions for various corporate and independent projects. His expertise lies in the field of motion graphics and compositing.