Hey there, Matt again with the Maya Learning Channel.
So alongside the Maya 2020 release I did a video showing you the newly exposed
Remesh and Retopologize features.
These let you selectively add detail to a mesh, evenly distribute faces,
and improve awful tri topology into better quad topology.
However, one of the limiting factors for Retopologizing is the fact that
it needs a relatively clean mesh to work with –
the algorithm has trouble dealing with things like holes, lamina faces,
and especially nonmanifold geometry.
Many of you pointed out (and rightfully so), how painful it is to clean up meshes manually –
I even said as much in the video itself.
But it was this comment by user Bruno Ortolland
(coincidentally the author of this cute baby Cthulu) that really caught my attention.
In it he mentions voxel remeshing, a process that rebuilds a mesh using voxels (3D pixels)
derived from the original mesh.
That got me thinking about another recent Maya plug-in – Bifrost.
See, Bifrost is really good at manipulating geometry in all sorts of custom ways,
including voxelization – could that be a solution?
As it turns out, yes!
So let’s make a compound to voxelize this into a new, clean mesh,
which we can turn around use for Retopologization!
So here again is baby Cthulu, complete with terrible topology -
including holes, nonmanifold internal faces, and more.
If I run a Cleanup function, look at all the problem vertices there are.
To start our compound, I’ll open the Bifrost Graph Editor...
and middle-drag the mesh into a new graph.
Now to voxelize it, I’m going to plug it into a “convert_to_volume” node.
Then to see the result, I’ll output the volume.
Now if I move the BIF object aside, you can see we have this sort of
“gassy” version of baby Cthulu.
To solidify him a bit more, I’m going to go back to the convert_to_volume node,
disable “Store Fog Density”, and turn on “Store Level Set”.
This also readies him for the next node we're going to use...
which is called “countour_dual_marching_cubes”.
Funny name aside, this node basically “crawls” the contours of a level set
to generate Bifrost geometry.
Of course, the default resolution looks pretty crude.
But because this is Bifrost we’re talking about, I can very easily dial up that resolution
just by reducing the Detail Size of the volume conversion.
Not bad eh? So now that I’ve got a Bifrost mesh I’m happy with,
I just need to convert it into a Maya mesh.
To do that, I’ll go into the Node Editor...
...then middle-drag in my Bifrost node…
...and plug the output into a “bifrostGeoToMaya” node…
Finally, this converted geometry needs a shape node to plug into.
It doesn’t really matter what shape node really, so I’ll just make a sphere and set it aside...
Then I'll delete its helper, and feed it the Bifrost output instead...
...which turns it into a baby Cthulu too!
Now I have 3 meshes: the original, the Bifrost output, and the new Maya mesh!
But notice that if I run a Cleanup command on this new mesh...
…Maya doesn’t find anything to clean up!
That's because voxelizing and rebuilding the mesh in Bifrost has automatically fixed
all my holes, lamina faces, and nonmanifold geometry!
In fact, all that's left is some internal faces,
which I can easily get rid of using Mesh > Separate.
And now my mesh is ready for Remesh and Retopo!
Now you might think to yourself “but look at all the detail you lose between each step.”
But remember: each step along the way is fully customizable!
Don't like the voxelized mesh? Decrease the volume’s Detail Size!
Want more out of Remesh and Retopo?
Play around with the Edge Length and Face Count!
Sure, more detail means more compute time, but doing things this way is lot easier
than going in by hand and cleaning it up yourself.
Not to mention the versatile options ensure you get exactly as much detail as you need
for the project you're working on – high end, low end, or anywhere in between.
And once I'm done, I can bundle my handy little voxelization compound up
for future use by myself or anyone else I want to share it with!
If nothing else, this is just another example of how Bifrost can enhance even
every day, non-effects workflows.
I'll post the finished compound to the AREA and put a link in the description once it's up.
Then all that's left to do is transfer the UVs over like I showed in the other video
and you're done!
Upon discovering this, I just had to try and squeeze a video in before the new year,
so I hope it helps you out.
And on a personal note, I'd just like to wish you all a happy holiday! See you next year!