Character Creation Module 07

Creating Topology for Production

Introduction
Welcome to Module_08!!

The emergence of high poly sculpting software has done many incredible things for concept art and digital sculpting in the Entertainment Industry. They let your creativity come first, but knowing how to get your creation ready for down stream consumption by other departments is still of paramount importance if you are working in any kind of collaborative production environment. In this module we will be covering many of the fundamental techniques that seem to have gotten lost in the high-poly shuffle, as well as some newer thoughts on topology layout.

To reiterate a few key thoughts from last week you do not have to be finished with your design sculpt to be able to follow along with the next stages of the process. To step through the forthcoming technical aspects of the work flow you only need a mesh that showcases some level of refinement. You can even choose to use a small portion of your mesh. If you sculpted your character from the torso up, you might choose to only retopologize the head. In other words, take small bites. Ideally, before you retopologize anything, your entire design would be locked, but for the sake of this class, and getting the most out of the module, we can make an exception to that rule.

Define the Pipeline
Before you create an animatable mesh you need to know what type of pipeline it will be used in. We are all aware that a mesh for a video game is going to look drastically different than a mesh for a feature film, but it’s also worth pointing out that a mesh can have different requirements depending on if it is intended for live action or feature animation.

Above is an animation mesh similar to the level you might see for a medium res character in a live action feature film. This is an all quad mesh which is much more difficult to accomplish but will deform and subdivide much better than a mesh with triangles. Notice how the edge flow or “loops” conforms to the major forms. We’ll be covering the importance of these edge loops and their layout in the accompanying video lecture. It is not uncommon to see an animation mesh for live action that is 20% to 50% denser than the one featured above.

This mesh is similar to what you would find in an animated feature film. The overall forms are much more simplistic than the previous example. However, they are also more refined. Achieving a clean surface on this type of character is truly a craft. Many beginners are fooled into thinking that “stylized” characters are easier to create. In many ways the opposite is true. Animated feature characters often lack a strong texture or extreme displacement that would otherwise hide surface imperfections. Refining the surface on this type of character is not an easy step and must be done with extreme care. We will take a closer look at refining the surface of this model in the following video lecture.

In both cases the meshes are built for a poly to subdivision pipeline. As this is the most common pipeline in the industry today (outside of in-game models), it is important to understand how the proximity of edge loops will effect the mesh once it is converted to a subD surface.

The horn grooves in the images above illustrate how the proximity of edge loops translates when the poly mesh is converted into a subdivision mesh. Notice how close to one another the edge loops are around the grooves in the horns (see top photo- poly mesh). This allows for a tighter line of definition around the groove once the mesh is converted into a subdivision surface.

Placement and orientation of edge loops
Deciding the correct placement of edge loops and integrating them into an evenly spaced all quad mesh is not an easy task. In fact, it is my least favorite step when creating an animatable mesh. New stand alone software like TopoGun and plugins like NEX for Maya are specifically geared towards making this step easier. I would highly recommend either option. No matter what approach you use, if you don’t know why you are placing edge loops in certain areas then being able to place them faster won’t necessarily help. One simple visual analogy for understanding the function of edge loops can be found in the image below.

Not only is it an awesome instrument, it’s a great way to understand the functionality of an edge loop. Think of your edge loops as the black lines in the center section of this accordion. Their orientation allows for a nice, fluid compression in a horizontal direction. Whenever possible you want your edge loops to flow in the direction they will need to compress.

Notice how the edges that follow the fold create a much cleaner result. If the edge loops do not flow properly the surface irregularities are only exemplified when a mesh is animated. Clean edge loops that follow the form allow a rigger (the person who sets up the model for animation) to create much cleaner deformations, minimizing results like the ones shown in the last surface pictured above.

Mo’ videos!

 

https://vimeo.com/41055421

Video: Mesh Layout, General

  • Importance of an edge loop
  • Building meshes based on a subdivision pipeline
  • Edge proximity during smoothing
  • All quads
  • Stars, five points come together
  • Stars on the same edge loop when possible
  • Defining major forms with edges
  • Continuous edge loops around flex areas
  • Avoiding edge spirals
  • Edge proximity for animation

 

https://vimeo.com/41142666

Video: Mesh Layout, Specifics

  • Eye socket, edge proximity, number of spans on eyelid, edge that defines outer edge of eyelid
  • Lips, continuous edge loop, edge proximity, top to bottom span match
  • Nasal Labial fold
  • Leg to pelvis approaches
  • Hand layout- with fingernails
  • Bald for hair
  • Mouth sock, angle, gum intersection, top to bottom lip edge lineup, outer loop to define end of lips
  • Reading the form

 

https://vimeo.com/41057188

Video: Cloth for Simulation

  • Straight lines for cloth
  • Penetration with body
  • Penetration with other cloth layers (similar density on each mesh when possible)
  • Density relative to body mesh
  • Avoid stars on edges

 

https://vimeo.com/41082327

Video: Misc Extras

  • Straps and accessories
  • Teeth, tongue and gums
  • Eyes, one or two concentric spheres
  • Hair proxy
  • Use cleanup mesh in Maya (or equivalent) to check for potential problems

 

Retopologizing in ZBrush
When it comes to retopologizing, ZBrush may not be the best tool out there, but it will get the job done. As an overview point, if the mesh is symmetrical I usually retopo half of the model in ZBrush, then export and mirror in Maya. This work flow makes more sense for me as I need to finalize the mesh in Maya anyway and it gives a more exact mirror than ZBrush. There are quite a few videos and notes on using the retopology tools in ZBrush online. I’ve created an overview video to get you started, but I would also recommend doing a little advanced searching on your own.

One quick update to this video: You no longer need to do the rigging step in this process! You just need to add a ZSphere then go to the Topology tab and click Edit Topology. Much easier!!!

https://vimeo.com/41148606

Video: Retopologizing in ZBrush

  • Place a ZSphere on the canvas (ZBrush needs a ZSphere to start the retopo process)
  • Link the mesh you want to retopologize to the Zsphere
  • Click on your mesh to begin drawing your new topology

 

Assignment: Retopologize your mesh with proper edge loops, form development, and animation in mind.

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Added

https://vimeo.com/46618053

Video: Mesh Layout, General

  • Importance of an edge loop
  • Edge proximity around lips
  • Stars on the same edge loop when possible
  • Edges around hip
  • Continuous edge loops around flex areas
  • Avoiding edge spirals

 

https://vimeo.com/47359800

Video: Mesh Layout, General and Specifics

  • Importance of an edge loop
  • Edge proximity around lips
  • Avoid elongated polys
  • Stars on the same edge loop when possible
  • Edge loop placement around hip
  • Edge loop placement for finger joints
  • Avoiding edge spirals