by Plakkie


This is a user-created and user-maintained tutorial, originally created in the ZBrushCentral forum thread [Tens de ter uma conta e sessão iniciada para poderes visualizar este link] You'll find additional information there. Thanks to Plakkie and all of the other contributors!

Contents [hide] 1 Introduction 2 Quickstart guide 3 General controls 4 Editing existing topology 5 Creating a topology mesh over a ZSphere model 6 Topology Mesh Extraction 7 Further Information 8 Frequently Asked Questions

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Introduction


The retopo tool can be used with a number of different artistic or
technical goals in mind. Consider the following usage scenario:
An artist creates a sculpted mesh in ZBrush that originates
from a ZSphere or Polymesh, without taking the overall flow of the mesh
into consideration. If the generated mesh topology (or polygon layout)
is not ideal for the subject, the retopo tool allows the artist to
reconfigure the mesh to meet their specific requirements. By applying
new topology to the target mesh, the user can be creative without
considering the base mesh, meshflow or seams of the target mesh.
The process of refactoring the polygon layout and tweaking a
copy of the base high-resolution mesh is called retopolizing. The
artist factors in polygon loops, animation, effects, rigging and
anything else that is important after creating the high resolution
mesh. If desired, a low polygon mesh (retopolized) is retained. This
mesh may also be subdivided and have details of the high-resolution
version projected on it. Please see video example at the bottom which illustrates the concept of mesh deformation abstraction.
[edit]
Quickstart guide

1. Load in your model (must be a polymesh, the standard primitives don't work)
   
2. Go to 3D Edit mode , if it's not already active (t key).
   
3. Click on the ZSphere tool in the Tool menu. Now a ZSphere will appear automatically.
   
4. In the Tool menu two new options have appeared: Rigging, and Topology. In Rigging, press 'select' and select your model that you want to edit.
   
5. In Topology select Edit Topology. Now you can start drawing lines.
   

Andreseloy has made a ZScript to show the basic procedure.
[edit]
General controls


(click means a standard mouse click, i.e. using the left button.)

• To add a point: click on desired spot.
  
• To delete a point: ALT-click on point.
  
• To set a new starting point: CTRL-click on point.
  
• To select a point: LMB-click on the point.
  
• To deselect a point: LMB-click outside your model.
  
• To move points: go from Draw mode to Move mode.
  
• To move more points together: increase the draw size.
  
• To scale points: go to Scale mode. (works best with larger draw size)
  
• To delete a connection-line without deleting the connected
  points: insert a new point in the middle of the line and delete that
  point.
  

Note:
Sometimes certain points won't move at all. Chances are you have
accidently masked them (you can't see this). Unmasking the points makes
them move again. —Thomas Mahler
[edit]
Editing existing topology

1. Load the model you want to edit
   
2. Select a new ZSphere tool.
   
3. Clone your model.
   
4. Make sure that the subdiv level of the cloned model is at 1 or 2. (If you don't, it doesn't work! The original model can have as many subdiv levels as you like)
   
5. In the Tool:Rigging subpalette, select the original model, and activate (optional) the Projection Mode, so that the model which will be generated is projected on the Template.
   
6. In the Tool:Topology subpalette, select the cloned model. All the lines will show up.
   
7. Enter the Edit Topology Mode.
   

With a big thanks to Francois Rimasson for his wonderful tutorial!
Here's Plakkie's ZScript showing how to edit existing topology.
Bonecradle has made this PDF tutorial showing this workflow on an imported .obj file.
[edit]
Creating a topology mesh over a ZSphere model


You can create a skeleton of ZSpheres and wrap it with a topology
mesh, while still being able to use the ZSphere skeleton as a rig!

1. Create a skeleton of ZSpheres just like the ones you use in ZSphere modeling.
   
2. Under Tools:Topology, click on Edit Topology.
   
3. In the Transform menu, activate the buttons: >X< , and the key to it all: Local ZSphere-Symmetry (Local Radial Count-Value determines how many lines will be drawn around the ZSphere skeleton).
   
4. Activate Draw mode.
   
5. Set your starting point with Ctrl + LMBclick on the desired spot on your ZSphere structure.
   
6. Click, release, move a little bit and click again. Around the ZSphere skeleton appears a topology!
   
7. Preview the mesh with the a key.
   
8. To use the ZSphere skeleton as a rig to pose your new mesh, deactivate the button Edit Topology and you can deform (Move, Scale etc.) the skeleton again; the created topology will follow the rig.
   
9. After you have finished your topology mesh, you transfer it into a skin mesh by Tool:Adaptive Skin:Make Adaptive Skin. Note that Edit Topology must be deactivated for that.
   
10. Now select the ZSphere skeleton as the active tool and scale the ZSpheres somewhat smaller so they fit all inside the new mesh.
    
11. Now press Tool:Rigging:Select and select your new created mesh , click Bind, et voilà, your mesh has a cool rig.
    

Note: When retopoing zspheres, under Display Properties
you can size them so they show smaller than the skin/rig you are
making. You can also quickly shrink down the ZSpheres for doing things
like fingers, then scale them back up. —Crusoe the Painter
Note:
You can turn edit topology off, add more zspheres, and then turn it
back on! Then you can add more mesh-zspheres, connect them up, et
voila! So if you make a bust, and later want to give it a body, you
can, as long you saved the bust zsphere rig! —Crusoe the Painter



Rastaman is currently exploring this under-documentd technique. He's made a more detailed and illustrated tutorial. Check it out!
He also made this ZScript showing this technique.
[edit]
Topology Mesh Extraction


With the topology tool you can easily create extra geometry like
clothing, armor, etc. In comparison with the Mesh Extraction tool you
have more control over the topology of the created geometry.

1. Setup a model for topologizing as shown above.
   
2. Set Tool:Topology:Skin thickness to 1. This will give the geometry shown in preview, (a key, some thickness. Smaller values, thinner geometry.
   
3. When finished drawing topology press Tool:Adaptive Skin:Make adaptive Skin.
   
4. The new geometry can now be put into the subtool list of your original model if you wish.
   

Here's a ZScript showing topology extraction, made by The Namek.


[edit]
Further Information


Topology in action:

• Movie by Thomas Mahler
  
• Thomas does a nose job
  

[edit]
Frequently Asked Questions


Q. How do I show the wireframe model?

Transform: Quick on and Transform: Frame on. Shows the polygons (The Namek)
Extra info: Or the Frame button on the shelf. (Plakkie)

Q. How to delete a point ?

Alt Click on a point to delete it (Kramskoi)

Q. Is there a way to weld the points ?

Not at this time.

Q. Is there a way to adjust your topology in Move mode while forcing
the vertex moved to remain on the surface of the underlying model?

Moving created points breaks them away from their on-model
position., as demonstrated by Bisenberger. At the moment it seems like
that's inevitable. Something for ZBrush 3.5? (Plakkie)

Q. Is there a way to save a topology rig in progress?

Just Deactivate the Edit Topology Button, and then save the
active ZTool, after reloading the ZTool, just activate the Edit
Topology Button again, and work further. (Mouse_art)

Q. Is there a way to create a mesh from the topolines that match up exactly?

To use the exact amount of polygons as you draw, set Tool:
Adaptive Skin: Density to 1 and Tool: Topology: Subdiv to 1.
(Mouse_art)
Extra Info:you have to set Adaptive Skin Membrane (Mbr) to 0
if you want the low res for your new mesh to match the poly count from
your retopo rig. I think Mbr defaults to 2 instead. I figured that out
the first time I created a skin from my retopo rig. The weird part was
that I could not get Reconstruct Subdiv to work on the skin. So I
deleted it, changed the Mbr setting to 0 and made a new adaptive skin.
(Poda)
While Edit Topology is on, you can press Shift and draw on the
model to automatically draw topology lines from the existing topology.


Q. Is there a way to transfer the high sub details to the new mesh?

Yes! Turn on the 'projection button' in Tool:Rigging. (Ladysoul)

Q. Is there a way to convert the original topology of a model into a
Topo-ZSphere structure, so you can edit it a bit instead of having
first to draw all the topo-lines?

Yes! The procedure is explained in detail at the top of this thread under "Editing existing topology" (Poda/Plakkie)

Q. When you project your old details onto your new mesh, is there
any way to copy over your texture or poly painting info? Or do you need
to do retopolgizing before you do any texturing/painting?

If I understand correctly, polypainting stores the color
information directly 'in' the geometry. With the topology tool you are
making new geometry, and thus your polypainted info doesn't apply on
the new model. I don't know about texture maps, yet. I think it's a
good idea to do the texture/paint part after you have made the new
topology. Anyone had different experiences? (Plakkie)
You can use the ZProject brush to transfer details from one
SubTool to another. Appending the new topology to the old topology as a
SubTool will allow you to use the ZProject brush to do this.

Q. When shifting topology vertices away from the mesh some of them
seem locked, couldn't move them at all. [more a statement really ]

You masked them by accident. Press Tool: Masking: Clear to unmask your mesh. Hit it twice if it doesn't go off at first.

Q. Are there some functions like "edge loop", "edge ring", "making strip" "split"... ?

Maybe some day, but not now. Those tools would really help
with retopoing zsphere armatures. Those things are still causing
problems. I'd rather have metablobs I can retopo (like Blender), than
trying to use Adaptive skin with ZSpheres to get a clean mesh. (Crusoe
the Painter)

Q. What's the quickest way to delete edges?

I am currently adding a new vert in the middle of the edge and
deleting (Ctrl+LMB click) that. The edge gets deleted in the process.
This seems to work fine but I would love to have a simpler, faster way.
I think i tried Ctrl+LMB clicking directly on the edge and something
bad happened.

Q. After working a little bit with the new topology tools, i tried
to create a new topology as described on the wiki. The mesh/tool was
created in ZBrush 2. When I hit the "edit Topology" button, i got a
skin with lots of holes in it, and I don't know why. Before hitting the
button the skin was ok! Does anyone know why this happens and how I can
fix this?

Solved this problem, by taking the topology of Subdivision lvl
2 of the Mesh. Lvl 1 didn't work and gave those strange holes...
(Train22)

Q. What do the Hide and Bind buttons in the Rigging and Topology menu do?

bind: allow to move the mesh reference. (Andreseloy)

Q. Is there any use for the Rotate mode?

None found...

Q. Is it possible to mirror an existing topology mesh?

Not at this time

Q: In section " Creating a topology mesh over a ZSphere model",
starting point for the mesh is defined with Ctrl + LMBclick, but when I
tried it I get a "mask" tool because Ctrl is pressed.

It works only when there is a topology present, but if there is
no topology made, than you can click anywhere on the structure and it
will start adding the topology).
Q: When making topology over zspheres sometimes my mesh is closed
(glass shape), sometimes it starts open (pipe shape). I couldn't find
any logic to see when it will be open and when closed. It's like
lottery, you see the result after adaptive skin preview. How to know
from the beggining what kind of mesh you are making?

Try setting Tool: Topology: Max Strip Length to 4. ZBrush, by
default, allows you to create a minimal number of topology lines that
it will try to connect for you. Depending on your needs, you can turn
this on or off with the Max Strip Length slider.]