PowerMesh is an exciting new tool available
in Mocha Pro 2021, think of it as a "sub-planar breakdown" for the Mocha planar tracking you
know and love. PowerMesh allows you to track organically
warping surfaces users used to have to break down into separate planar tracks. PowerMesh can be used for warped inserts,
paint, and to drive rotoscoping. In this quick overview, I will talk about
some of the most frequently asked questions about PowerMesh workflows. 1. Uniform vs Automatic Mesh Generation:
A lot of users are unsure of when to use uniform vs automatic mesh generation, and I think
it can be explained pretty simply. For things like faces and cloth, or for objects
you need to capture a lot of detail for, uniform can be a really good option, but for things
like bare skin and smooth organic objects, or for rotoscoping, automatic is a good choice. Furthermore, Automatic is very useful when
the general pixel pattern is constant, or when the surface is maybe more rigid, like
this chameleon skin, whereas when there are light shifts or areas of less detail, Uniform
is often a better choice. So for this shirt for example, I want to grab
the way the cloth is deforming with complexity so that I can put a graphic onto the shirt
and have it deform properly. So this is a good time to use uniform mesh
generation. My tracked mesh ends up looking like this,
very obviously following subtle movement in a uniform way. But for this arm, for example, I'd want to
use automatic mesh generation and that could help me drive roto shapes to cut down on manual
work. See how automatic mesh generation looks for
high contrast areas to focus on? This can really help cut down on bad tracking
data areas when tracking low texture objects. If there are not enough points in an automatic
generation you can use "adaptive contrast" to look for more detail in the object. Adaptive contrast only affects the mesh generation,
not the tracking, but I often find it helpful in mesh generation. And you can always adjust the mesh size to
be smaller when you need more detail for both uniform and automatic mesh generation. You can also hand edit a mesh to increase
the amount of detail in the faces and improve warp quality when you render. 2. Tracking inside edges and avoiding occlusions:
Unlike the Mocha Pro planar tracker, where you normally want to create your spline a
little outside the edges of the object you want to track, and where usually you break
the object up into paper doll shapes, you don't have to do that with PowerMesh. When tracking with PowerMesh you want to stay
inside the edges of the object because the mesh tracker is much more sensitive. You don't really have to think too hard about
how to break the object up as now one spline can cover multiple areas that are not co-planar. What you most need to pay attention to is
breaking objects up into foreground occlusion areas instead. So, for example, you’d want to track an
arm moving over a body as a shape separate from the body, but you don’t have to split
that arm up paper doll style anymore. PowerMesh is really sensitive to detail shifting,
so staying inside the edges of the object will ensure that your PowerMesh tracking areas
don't drift right off your object or get caught on a shadow. In this example, I’d track and roto the
arm first using PowerMesh and then stay inside the lines, then I’d use the Uber Key to
make the shape larger than the arm before I tracked the body layer underneath. You can also create a mesh in a larger shape
for the initial mesh creation, and then narrow the shape for mesh tracking. This is very helpful when an object rotates
a little or when you need to have a PowerMesh warp to the edges of an object, but you need
to avoid areas that would mess your track up. 3. Smoothness means planar tracking drives sub-planar
tracking: Smoothness is how much the PowerMesh respects
the underlying planar surface track or how much it diverges from the planar track. Think of this as starchiness, or how stiffly
the PowerMesh reacts to the track. For something like a piece of paper, I'd want
a higher smoothness, maybe 80 or 90. Just like this example, you can see the paper
reacts to the movement of the hand but does not wiggle too much. For something like water I'd want a very low
smoothness. Just like this. Notice how PowerMesh warps across the surface
in a nearly fractal pattern. And for tracking something like faces, I'd
stick to the default 50. That way I get some nice fleshy movement but
not a lot of jiggle that wouldn't make sense for skin. You can even stop your track and turn the
smoothness parameter up or down and keep tracking to solve very difficult shots. 4. Creating meshes with occlusion layers and
when not to: One of the major benefits to using Mocha organic
object tracking instead of some more automated optical flow solutions is taking advantage
of Mocha's occlusion workflow. This means you can hold out data that would
otherwise interrupt your tracking with inconvenient interference. You can also use it to hold out problem areas
on the same shape layer. So for this face for example, if I track the
eyes at the same time I am tracking my face, I can get some truly odd results. Creating occlusions inside your shape layer
makes sense when you are tracking faces but want to avoid blinking eyes, or when you are
tracking an object with a hole in the middle like a doughnut. However, creating meshes with occlusions on
the same layer doesn't make sense if you need to track behind something and the occlusions
move, so you'd want to create a mesh for a shirt with an arm moving over the top, with
the occlusion underneath the mesh for initial creation, but then you'd want to move the
occlusion roto above the mesh to track while avoiding that occlusion. With occlusion layers, make sure you make
the holdout shapes larger than you think you need, because as I mentioned earlier, the
PowerMesh is sensitive, and that’s a good thing, but not when it comes to occlusions.. 5. Editing points when things aren't quite perfect:
When your track is complete, you may find some points wiggle and wobble inappropriately,
when this happens you can either adjust smoothness and track again, or if you're happy with everything
but a few points you can hand adjust those points. To hand adjust points, select the point editing
tool and you can either adjust points individually... or select them in bulk using the lasso or
marquee selection tools. Simply scroll through your timeline and adjust
points just like you would in the Adjust Track module, look for the places where the points
most diverge from the desired location and then place them where you think they belong. The zoom window tool can really help you zero
in on detail areas to make sure you keep coming back to the correct featured area. Now I have a much more accurate warp based
on a few simple hand corrections. You can also add more detail in the mesh by
adding points, this is really handy when a PowerMesh render is starting to look too angular,
you can add more mesh detail which will translate to more warp detail when you render. So for instance, in order to get a more accurate
track, I kept this mesh low detail while I tracked, but see how the render is a bit harsh
if I render this in the stabilize module? I can jump back to the track tab to add more
detail with the add points tool and now, back in the stabilize module, when I re-render
this mesh stabilize the distortion looks much nicer. PowerMesh is one of the most exciting new
features to be included in Mocha Pro in some time. We can’t wait to see how users create with
this powerful new tool. Check out our tutorials on Mocha Pro 2021s
new features to explore other workflows like Alembic Exports, Python Scripting, and Adjust
Track 2.0. To download a free trial, visit us at www.borisfx.com
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