Category : 3-D Modeling
Part three of Building a base mesh series. I use two boxes to model a foot and then layout UVs. Take notice that I make sure my foot has an octogon (8-sided polygon) at the top. This will be important when I put the pieces together.
Category : 3-D Modeling
Here is another sculpt stored in p3d.in. I used Decimation Master in ZBrush to reduce the file size and UV Master to preserve my colors. Using p3d.in, the viewer can pitch, roll and zoom in on a 3d object. Click inside the dark rectangle above to see how it works.
Category : 3-D Modeling
Using clay sculpting techniques for ZBrush
Start with a skull
Cut in for lips
Add a clay ball to begin sculpting the nose.
Add malar fat and other fat pads to fill in the face.
Add cylinders for the top eyelids
Add cylinders for the bottom eyelids
Smooth out the seams for the sculpture
Add zygomatic major
Refine the sculpture
Category : 3-D Modeling
In ZBrush tools can’t be retopologized without destroying existing 3D layers. In Blender, objects can be retopologized and existing Shape keys will be altered accordingly. The altered base object and its shape keys can then be reimported into ZBrush. The conversion is tedious work. I attempted using the GoB plugin, an unofficial GoZ for Blender, but the steps became even more tedious then simply exporting all the 3D layers as obj files. To do this tutorial, you will need the Corrective Shape Key script for Blender available for download at wiki.blender.org
Install the Corrective Shape Key script (Blender)
1) Download the script.
2) Open Blender.
3) Open User Preferences.
4) Click on Addons.
5) Click on Animation.
6) Click on Install from file and select the script.
7) Checkmark the script to the on postion.
You are now ready to use Corrective Shape Keys.
1) Open ZBrush.Steps for Conversion
2) Turn off group under Export and export the main object.
3) Turn on the first 3D layer in the layer palette.
4) Export the obj with the applied layer using a different name. I name them after the 3D layer.
5) Turn off the selected layer, turn on the next 3D layer and repeat steps 3 and 4 until all layers have been exported.
6) Open Blender.
7) Import all the obj files.
8) Type B to do a box select then select all imported objects. Type CTRL A and select location then type CTRL A again to select rotation.
9) Select the base object using the Outliner.
10) For the base object under Object Data > Shape Keys click the plus sign to add a new Shape Key called “Basis”.
11) For each 3D layer obj, select the morphed object first then select the base object. Use the Outliner to do this selection.
12) Under Object Data > Shape Keys click on the downward triangle and select Add as corrective pose shape (fast, armatures only)
13) A new shape key should have been added based on the name of the morphed object.n You can rename it as you see fit. Turn off the new shape key by clicking on the eye.
14) Click on “Basis” then repeat steps 9 to 12 for all the morphed objects.Please Not, if you miss the step, you will overwrite your previous shape key with the new one.
You can now modify the geometry of your base object and the changes will be propagated to all the shape keys. Unfortunately you cannot work in mirror mode to edit your topology so check both sides frequently with each edit.
Back to ZBrush
1) In Blender export the obj file with NO SHAPE KEYS APPLIED.
2) In Blender, for each shape key, turn on the shape key and export it as a new obj file. Turn it off after the export.
3) Once done exporting all the morphs, open ZBrush and import the base obj.
4) For each morph obj, add a new layer in ZBrush and keep it in record mode.
5) Import a morph. This automatically turns a morph object int0 a 3D layer.
6) Turn off record and click on the eye to hide the morph.
7) Rename the layer to keep track of which morphs have been added
8)Repeat until done.
Category : 3-D Modeling
Here is a visual demonstration of what a good base mesh can be. All the faces in this article were built off the same base mesh, which can be downloaded at the end of this article. I developed this base mesh after running into sculpting problems with my previous meshes. I made a conscious effort to replicate the muscle and bone structure of a real face while at the same time leaving a low enough poly-count that the mesh could still be adapted to different faces. The development of this mesh owes a lot to ZBrush Studio Projects: Realistic Game Characters by Ryan Kingslien and L’Ecorche iPhone/iPad app by Michael Defeo and Scott Eaton.
Method of Production
Eyes, eyebrows, hair and, eyelashes were all done as separate ZTools. I used mask extraction to create the eyebrows and eyelashes. I appended a polysphere for most of the hair. The dreads were done using the Curve Multitubes brush. My five most frequently used brushes were Move Topological, Inflate, Trim Dynamic, Damian Standard (Dam Standard) and Smooth. These scupltures can be seen in the round on my Youtube Channel.
Click here to download my base mesh bust. You can auto-polygroup the model using the existing UVs I created for it. It consists of 1034 quads and weighs in at 143 KB.
Category : 3-D Modeling
Quad is short for quadrilateral, a 4 sided shape. Quad meshes are ideal for digital sculpting and 3d animation. Sculpting on a mesh with a mixture of quads and non quads can result in pinching and sharp angles in unwanted areas. Here I present some cases where polygons can be converted into quads.
1) Quad adjacent to a triangle
Add a line in the centre of the quad.
2) Two Quads adjacent to a pentagon (5 sided polygon)
Add a line to the centre of the pentagon.
3) septagon (7 sided polygon) sandwiched between 4 quads and 2 quads
Split the septagon as shown.
4) Ring of triangles (even number)
Remove half the lines to merge triangles into quads.
5) Ring of Triangles (odd number)
Remove half the lines and add a point to the remaining triangle.
Category : 3-D Modeling
Topology matters.
When building 3d models I’ve seen time and time again that topology can affect how a model bends, how it looks in certain lighting and even how well it can be morphed. When sculpting a poorly topologized base mesh in ZBrush, I have found myself fighting against the tendencies of the underlying shape. It wants to fold where I want it to expand. Triangles in the wrong spots can cause unsightly bumps when subdivided again making sculpting difficult.
Experience has taught me that correcting bad topology can often take longer than simply building the right topology in the first place. Having a good base mesh increases artistic productivity by reducing the time it takes to build a figure completely from scratch. Creating your own base mesh also helps you to create more original figures for your portfolio.
I generally create my base meshes in Silo and then sculpt then in ZBrush. Although these guidelines are based upon my workflow they could easily be applied to Blender, Maya or any other tool that allows for sculpting and edge loop creation.
Here are some guidelines for making the topology of human base meshes that I have found useful along with practical examples:
1) Use quads over most of the figure.
Programs like Blender, Silo and ZBrush give the artist the power to increase detail in a model through subdivision. As I’ve mentioned in previous posts, subdivision works best with quads (4 sided shapes). Some triangles in hidden areas (e.g. nostrils) are fine since they won’t be seen. As much as possible avoid using triangles.
2) For a base mesh, use the least number of quads possible.
With subdivision, less is more. It is easy to put too much detail into a base mesh and end up with a figure that is too specific and not general enough to be molded into the desired character. Try to keep features vague so they can easily be manipulated later. With vague details you can make dramatic changes in your figure at a low subdivision level and project the results on a high level.
Always try to reduce the number of quads you put into your base mesh. Try viewing your mesh with subdivision with some edge loops removed. If the effect is undesirable don’t forget CTRL-Z or CMD-Z.
3) Use larger quads on the body and smaller quads on the face.
Generally, more detail is required for the face than the figure especially for complex features like the ears and the nose. Having more geometry to work with makes it easier to form the desired figure and reduces texture stretching when the figure is painted.
4) Mimic the underlying musculature and skeleton of the figure in the placement of quads.
When quads mimic the underlying structure it becomes much easier to create realism in the final figure. You won’t have to fight the mesh to emphasize structures in your model. A good base mesh will help you sculpt. Visual reference is especially useful for this purpose. One source for visual reference that every 3D artist should know about is http://www.3d.sk
Placing quads to match important landmarks on the body (e.g. eyes, nose, lips, collar bones, hips) makes the sculpt easier. The base mesh reminds the sculptor “this is where to place a feature”. It also helps to maintain the form as it is sculpted.
5) Be prepared to star over.
In writing this article, I created a base mesh I was reasonably happy with and found myself becoming unhappy as I sculpted on it. I had to go back to the drawing board and change some edge loops. The newer mesh sculpted better but this is an iterative process. I will update the mesh as my skill level increases. Improvement always requires refinement.
For more information, visit these sites:
Category : 3-D Modeling
Update Jan 29, 2013: Even with ZBrush 4 Release 5, QRemesher and the topology brush, the dream of never having to do manual retopology is just that a dream. Manual still gives the best results, although I am sure Pixologic will improve their algorithms. The title of the article is a bit misleading but I keep it for historical purposes.
Update Oct 8, 2011: Free ZBrush 4 Release 2 Tutorials from Pixologic
DynaMesh is a new feature of ZBrush 4 release 2 that allows the user to add to a mesh while at the same time maintaining an evenly distributed topology! What is even better about DynaMesh is that the new topology is mostly made of quads, making it easier to sculpt in ZBrush and animate in other 3D apps. I am not certain but I suspect this instant retopology technology was borrowed from Sculptris after it was acquired by Pixologic. The main difference between Sculptris and ZBrush with instant retopology is that Sculptris only uses triangles whereas ZBrush uses mostly quads. While DynaMesh reduces the work required for retopology it is not perfect. Stray triangles may appear in the retopologized surface that will need to be edited out manually.
To make use of DynaMesh, here are the steps.
Once DynaMesh is enabled, ZBrush can automatically retopologize your mesh every time you hold down the control key while clicking and dragging on the canvas. Simply clicking and dragging turns sculpted features into a more uniform mesh and maintains quads for most of the new retopologized mesh. This is useful for fixing topology after stretching a model with the Morph Elastic Brush or the Snake Hook Brush.
Dynamesh really shines when retopologizing after inserting a mesh. ZBrush 4 Realase 2 has added a number of “Insertion Brushes” which allow the artist to add meshes to the current mesh. In my example I inserted a nose on a sphere. Control clicking and dragging will combine the old mesh with the inserted mesh. The combined mesh will again be composed mostly of quads with no breaks between the previously separate meshes. To prevent two meshes from being combined, remember to use Group split before remeshing to turn them into separate subtools.
You can also control the resolution of your retoplogized mesh with the slider underneath the DynaMesh button. Increasing the slider before remeshing creates a finer mesh. Decreasing the slider before remeshing creates a coarser mesh.
Below is my DynaMesh example sped up 5 times.
