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ZBrush 3D Modeling for Adobe Atmosphere?
Part 2 - An Example Project
If you are wondering what
a typical modeling project is like in ZB, here is a sample. Below, I'll lead
you through a fairly typical work-flow to produce a simple 3D model for
Atmosphere. And to get a feel for how hard it is for a 3D modeling and ZB newbie
to use ZBrush, just remember that this is only my 2nd ZB projects, so i'm still
an official newbie. I admit to looking at modeling for years though, and have
tried a couple of things in the past. So I am familiar with some of the concepts
and industry standard methods.
In ZB, you start by sculpting (based on either playing around freely, as I
did, or by using existing pencil sketches). You normally use a fantastic
sculpting tool called "ZSpheres". You create one of these magic spheres, then
keep adding more ZSpheres to it (up to several hundred). This fills out the
basic form of your model. You then stretch, rotate, move, scale and otherwise
manipulate these ZSpheres, to sculpt your model. Whenever you add one ZSpheres
to another, it creates gray link sections between the spheres, which you can
stretch, rotate, etc.
So, there I was, playing with ZSpheres, and learning about a special kind
called "Attractors". Attractor ZSpheres "pull" on your other ZSpheres, to deform
your model and easily make amazing smooth organic shapes.
As you sculpt,
you can preview what your set of ZSpheres will look like, after you "Skin" over
them, to create your polygon mesh. Even after you have a mesh, you can continue
modeling, adding or removing material from your model with very fine control,
such as through holes in masks and stencils.
Starting a model with ZSpheres:
When I saw this shape I had just made, I thought, "Hey, that looks like a
wing. Guess I'll make me a spaceship". Since you can create numbers of models
and later "glue them together", I next made a ship body.
Making a second part to add to the final model:
Notice the amazing power of the "Attractor" ZSpheres in creating the tail fin
and wing shapes by deforming the regular ZSpheres!
ZB lets you create perfectly symmetrical details from just one side of your
sculpture, with one movement. For example, the 2 wing stubs on the body and the
"fingers" of the gun shapes on the wings were made using "symmetry".
Using my new right wing and body models, I was ready to mirror copy the right
wing to make a left wing and to glue my model parts together. This is done
through a somewhat tricky process called a "Multi-Marker". It took a few tries
to get that working. However, the next step, skinning your model to make your
mesh, is a one-button affair.
Assembling and skinning:
With your skinning finished, it's time to start detailing. ZB has many
powerful tools for working on meshes directly. For example, I made a simple mask
in Photoshop, and masked off a section of the body as a "canopy" area. Then I
tripled the number of polys in that area, in order to get a smooth surface and
precise edges for my 3D canopy.
After making the mask cover a smaller
area for the actual canopy, I "deflated" the model a bit, just through the hole
in the mask, to make the 3D sunken canopy. Then I painted the canopy blue, also
through the mask. With all the extra polys in and around the canopy, it came out
nice and smooth.
Working directly with the mesh:
Next, I started on the texturing. The ZB manual says that model
realism is 20% in the sculpting and 80% in the texturing, so I was anxious to
try my hand at applying a texture that I could detail very finely in
Photoshop.
My first texture was a messy disaster. Turning to the friendly
ZB forum, I found that I had neglected to preview and perfect my UV mapping!
With the help of the free UV Mapper program, I was able to apply two different
UV maps, ending up with a much better mapping for each part of my model. Below,
I test the effectiveness of my UV mapping by applying a checker pattern to the
model. Oops, look how coarse the mapping is on the back. But I was getting
impatient, and went on to painting, rather than improving the UV
map.
UV Mapping for textures:
Starting with a white, fairly glossy texture, I unwrapped and exported the
ship texture to Photoshop and proceeded to paint in surface
details.
Detailing a texture in Photoshop:
When I was satisfied with my texture, I was pretty much finished. I could
have also done custom lighting or added more 3D bits, such as an engine in the
hole in the back - or even continued to sculpt. ZB is very flexible that
way.
And you can save everything, every step of the way, so it’s easy to go back
to any point, or to reuse your models or textures for other purposes. Most ZB
users would also have put their new model into a ZB painting, perhaps adding a
starry backdrop, laser flashes from the guns, etc. But I’m more interested in
models for Atmosphere, so my next step was the usual export to Viewpoint Scene
Builder and import into Atmo.
Here is the finished model, as seen in ZB. In Scene Builder it looks just the
same, except for the usual Viewpoint lighting shine. I have yet to try making
the ZB standard *.obj light maps work in Scene Builder, rather than using Scene
Builder's lighting. When exported from ZB, this model has 35,727 polys - not too
bad for a first try. The Viewpoint Scene Builder MTS file is a large 461,000
though. I could have optimized it in ZB, or used Zilly's MTSTakeDown and
probably cut that to perhaps 30%. An exercise for next time. And speaking of
next, ZB will soon have the fantastic
displacement mapping, allowing
extreme detail with very small poly size, from models with millions of polys. So
I'm not too concerned about learning to be stingy with the polys.
The finished 3D model, ready to export to Viewpoint Scene Builder:
What went wrong?:
I learned a lot on this project, and not only about ZBrush. One of my lessons
was the trade off between the number of polys and the detail one can get in
texture painting. As you can see from the UV Mapping picture, the tail fin and
back part of the body have too few polys to carry their texture, compared with
the rest of the model. That is why the surface details on the back part of my
model are blurred. Next time, I'll double the polys in that area.
Incidentally, this model took me 6 to 8 hours, plus a few for study time. But
I could probably do it again in 2 or 3 hours.
So, is ZBrush hard? It's
not as hard as doing without your own 3d modeling skills. Nor is it as hard as
most other 3D solid modeling programs.
Happy
Atmosphere Building!
--jim coe
Please be sure to check out Jim Coe's website at http://wellmadewebs.com/public/atmo/atmo-main.html.
To view some great worlds that Jim has built Click Here.
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