CG Tech - Manual Retopologisation & UVing #01

Manual Retopo & UV layout

Once the voxel sculpt is complete there are 2 options for retopo. The 'AUTOTOPO' function or.. going it alone. In this example I have chosen to retopologise by hand. 

In the 'Retopo' tab within 3D-Coat there are a few key tools that help to retopo quickly and efficiently. Those are:

Strokes - 

Quads - 

Digital Compositing - Rotoscoping #01

Rotoscoping - Separating elements from a shot by tracing around them, essentially.

First of all I added a 'grade' node to the original footage to adjust the white/black levels. This made the footage have more contrast, and therefore made it easier to track.

A 'Roto' node was the added (shortcut key 'O' in the node graph). using the bezier tools I then divided the rabbit up into sections as seen in the 'roto' node's layer panel (fig.5). Starting from some key positions in the footage where the rabbit is most exposed, I used the bezier tool to trace around the separate limbs. This was made easier by adjusting the opacity of the roto-shapes so i could see through to the background plate (fig.1)

Roto shapes have the ability to feather using small handles on each bezier point. The feather is indicated by the dotted line, the shape by the solid line (fig.2). 

Once one frame is done, you move to the next significant frame and transform the shapes to once again fit the  subject you are tracing (fig.3). The software will automatically key the frames where alterations were made, key frames are shown in blue on the timeline (fig.7).

Nuke will also tween from key-frame to key-frame.

The process of moving the shapes to fit each frame continues until you have a complete rotoscope.

The final result will be a moving silhouette of the object/creature you traced (fig.4 shows the resultant Alpha).

The node graph is shown in fig.6.

Sequential Art

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Digital Compositing - Nuke Tracking #01

Aim: To replace the picture in the frame with another image.

We start by importing the assets into the node graph.

We then attach a 'Tracker' node to the original footage. To start with there will only be one tracker activated on the screen, (fig.1) the inner square indicates the target feature to be tracked, the outer square indicates the area to be searched in the following frame. 

You can then activate up to 3 more trackers per tracker node by ticking the box labeled 'enable' in the node properties panel.

Line up the trackers to the features you want to track. (note that if you are tracking 4 corners the trackers need to be placed on the correct positions: 1=bottom left, 2=bottom right, 3=top right, 4=top left)(fig.2)

to track press the play button in the Tracker node properties panel. 

Now that the track is complete, attach a 'CornerPin' node to the replacement image. We then need to feed the information from the 'tracker' node into the 'cornerpin' node. This is done by Ctrl + LMB-Click-Dragging from the tracked data in the 'tracker' node properties panel to the corresponding parts of the 'cornerpin' node's properties panel. (fig.3) This creates a live link between the two nodes shown by the green pipe.

The 'tracker' node can now be disconnected from the source footage as the data is now stored within the node.

The foreground and background can now be merged. If the image does not match up exactly to the frame (fig.4) a 'transform' node can be applied to the replacement image, where it can be distorted until it fits correctly. (fig.5)

The complete Node Graph is shown in (fig.6) with an additional 'grade' node for basic colour correction.

Visual Effects - Matchmoving #01

For this Visual Effects Assignment, I plan to do all of my 3D Camera/Object Tracking in Boujou 5.0

Above are a few reference screen shots to aid my explanations, as well as to jog my memory for future endeavors   

The 'Boujou Toolbox' (fig.1) is located on the left hand side of the Boujou interface when first opening the program, this contains a lot of the tools necessary to complete a tracking task. New buttons can be added to the toolbox simply by clicking the right mouse button and selecting the feature you want from the menu that appears.

One of the first steps to undertake when tracking is to assess the lens distortion of your footage (fig.2). This removes possible anomalies from your track and makes for a much easier time when adding scene geometry later in  process. it can also provide better results than tracking a distorted piece of footage.

In (fig.3) it is necessary to turn on 'Radial' in the 'Overlays' tab so that the corrected footage is seen in the view-port.

After the distortion is corrected, you are then ready to track the features of the image sequence (fig.4). initially you may want to adjust the amount of points you track to reduce the tracking time, the more detail you put into the points, the longer the tracking process will take.

In (fig.5) you can see the result of tracking the features on a 2D plane. the automatic tracker generally does a good job of tracking the key features of high contrast. However it can miss some points which you may want to include. if this is the case then you can track them manually using 'Locators' and 'Target Tracks'. (Coming up in 3D Tracking #02)

If there are sections that you do not want to be tracked, such as moving shadows, or objects/people moving through your scene you may also want to mask out that section using the 'Add Poly Mask' tool.

Pre-Production and Short Film Making

My progress for this module should be charted at the team blog:

http://atcaaa.blogspot.co.uk/

CG Tech - Voxel Sculpting #01

The Brief: Design and then sculpt a biped in 3D-Coat using Voxel sculpting methods.

Voxel - Essentially a 3D pixel

1. The original sculpt was built on one layer starting with primitive spheres to block out the initial body shape. After the overall shape was established the 'Muscle' brush was used to bulk out the character and continue to refine the form. The legs were added on by using the 'Curves' tool (as seen in fig.3) and smoothing them into the main body shape. At this stage it was necessary to 'Res +' as artifacting around the eye sockets was beginning to occur.
2. The same basic processes were repeated to reach the stage shown in fig.2
However some pieces have been separated into different voxel layers (see fig.4). This is so that they do not marge with the structure of the body
3. As previously mentioned this screenshot shows the 'Curve' tool in action creating the underlying structure of the leg.
4. The VoxTree is essentially a layers tab. It houses all of the different voxel objects in your model and allows you to toggle their visibility as well as switch to a surface proxy mode for sculpting with a lot less memory/cpu usage. The '[2x]' next to some of the layer names indicates that they have been ressed up.