Lightwave to Zbrush and back again.
By Mike Green
There seems to be a lot of confusion over what you can and can't do
with the combination of Lightwave and Zbrush on the net, so I thought
I'd write this tutorial to try and clear some of that up. I've been
using Zbrush with Lightwave for a couple of months now and this is what
I understand to be accurate. I'm going to take you through th steps of
having a mesh in Lightwave and taking it into Zbrush and displacing it
there, and then applying that displacement back in Lightwave.
You'll need to be a little familiar with Lightwave, and have to
explore Zbrush on your own, though I do run through some of the basics.
Step 1: The Lightwave mesh.
I don't tend to use the modelling tools in zbrush like zspheres,
although they're fairly complete, since they lack one or two features I
use in LW and I find I can make up a rough low polygon object in LW
much faster than in Zbrush having used it for so long. I also like to
use the UV tools in LW to make my map, so that it's as optimal as I can
make it, and as understandable as I can make it. I find the auto UV
maps made in Zbrush tend to have a lot of seams, and aren't
out to make it easy for me to paint on should I go into photoshop
afterwards. So I've made my object in LW, and I've split the head from
the body in UV space, the body being in 0-1 U and the head being in 1-2
U. This means I can have a higher resolution displacement map for the face, since you'll be
looking at it the most. I'm going to use the same displacement map and
colour map for each half, so they're symmetrical, therefore I've
the object along the y-z plane, and moved the right side parts out to
2-3 and 3-4 in the U. I've called the body surface 1_BodyLeft and the head surface 2_HeadLeft and so on. When Zbrush outputs the
displacement maps, it'll use 1,2 etc as suffixes for each UV segment, 1
for the segment 0-1, 2 for segment 1-2, 3 for 2-3 and so on in U.
Naming our surfaces like this is more useful when you have a lot of
segments, so you can keep track of which displacement map .tif (the
filetype Zbrush uses) goes where later on.
Also, by grouping polygons of your object together
by using the View>Selection Sets>Create Part function in
Lightwave (for example Arms, Legs,
Body, Head) these will be exported in your .obj file (this is the file
Zbrush uses for polygon objects). Zbrush will pick these up as Groups
(how it groups polygons together),
and it will make it easier to hide parts of your object when you're
painting complex parts.
Step 2:Exporting to Zbrush
Once you have your mesh laid out as you want it, you have to save as a
.obj. You do this by using File>Export>Export OBJ.
Some things to
take note of are:
The .obj format (as I just said) respects Parts, Zbrush
bringing them in as Groups
If you want the .obj to store your UV map, you have to set
your surfaces to use the UVmap. You don't have to assign an image to
it, just add a texture to one of the surface's channels, and set it to
UVmap and select the UV map you have created. That's it. Now the .obj
will contain the UV map when you export it.
It's best if your object is quads, but Zbrush will work
with any mixture of quads and tris.
Be careful that your UV's don't overlap, as I've
crashes in Zbrush which could be tracked back to this. It's not a hard
rule, you might find Zbrush still works, but if Zbrush does crash
especially once you subdivide the mesh, and add a texture, this could
be the problem.
Step 3: Importing in Zbrush
Go to Tool>Import and select your exported .obj. Click and drag
the main viewport, and you'll see the object being drawn. It'll be
upside down, but if you drag around, you should be able to right it.
Immediately click the Edit button at the top of the window, and you'll
be able to paint and modify it. Click the Frame button, and you'll see
the mesh coloured according to the groups you have set up on your
object. Also, it's important to store a morph target (Tool>Morphs>Store MT) at this point, as
Zbrush uses this to determine where the mesh has been displaced and
generate the displacement/Normal maps later on.
Step 4: Working in Zbrush
From here you'll have to learn how to use Zbrush, but some useful tips
- Holding the Ctrl button while holding your cursor over a
menu item will give you a useful description of that function.
- Click-dragging anywhere in the view except on the object
rotate it. Alt-Dragging in the window except on the object will move
it. If you want to zoom, you hold down Alt, click and hold the left
mouse button then release the Alt button, and drag, and you can zoom in
- Ctrl-d will subdivide
your object to make it smoother so you can paint your deformations. You
can keep doing it till you hit your poly limit (set in the
Prefs>Mem>Maxpoly per mesh). Once it's subdivided,
go down the subdivision levels to more basic by pressing shift-d and go
back up to smoother by pressing
- You can save your work by going to Tool>SaveAs and save it as a .ztl
file. This will save your images, any alphas and the deformations on
the tool in the one file, so it's nice and easy and USEFUL to do this
- There are two main modes in Zbrush for painting on 3d
objects. Tool modification mode, and Projection Master mode.
- Since you've brought your object as
tool, using the Draw/Move/Rotate/Scale buttons in Tool modification
mode will paint only on your mesh. You can rotate around your mesh in
this mode. You can't use any other types of brush on it, just an
airbrush type brush. You can also paint different Materials on your
mesh, but these are on a per polygon basis, so the higher the
subdivisions on your object, the more precise the material can be
- You can also paint Colours (You'll need to create a Texture for this) on your
mesh. The material can be saved (kind of) as an alpha image.
- You have 10 different brush effects you can do, these are found in the Transform Menu :
- Std - bulges the surface along the average normal of the
- std dot -makes a dot which you can move around till you're
happy, then leave on the surface.
- Inflat - bulges the surface along the normal of each face.
- Inflat dot - like std dot, but using the inflate
- Morph - paint back to the morph target
- Morph dot
- Layer - paint a layer which is smooth and level till you
lift the brush and start painting again.
- Pinch - useful for wrinkles, but not suitable for
displacements as it moves adjacent faces towards each other, not up or
- Nudge - again, pushes poly around, so not really suitable
for displacement painting.
- Smooth - Smooths out deformations.
- You can also activate symmetry for your strokes, by clicking
the >X<,>Y<,>Z< buttons, or pressing the keys
x,y or z.
- You can invert the effect a brush has by pressing alt and
drawing on the mesh.
- If you hold down shift while drawing, this turns the tool
the smooth tool. You can reconfigure this by pressing shift and
clicking one of the other tools.
- To enter Projection master mode, press g to bring up the
Projection master panel.
This will basically 'Drop' your object onto the canvas and you'll be
able to use other brush types on it, but not to move or rotate it. If
you want to paint colours on your object in this mode, you will also
need an image assigned to your object before you go into the mode. You
can make one in zbrush or load one you've made already. Once you've
finished modifying your object, you'll be able to pick up your object
again (press g), and continue in tool modification mode. Which boxes
are ticked in PM mode will determine what lasting effects you have on
your mesh, and Zbrush gives you a preview of what will happen on the
spheres as you toggle the features on and off.
Step 5: The Multi Displacement Panel
Now you've painted your object's deformations, it's time to export your
deformations. First of all,
use shift-d to reduce your object down to it's lowest subdivision
level, just like it came in. ZB needs to be in this mode so it can
calculate the displacements from the base mesh. We're going to use the
Multi Displacement 2 exporter,
which is downloadable from www.pixelogic.com . You install it to
ZBrush2\ZStartup\Zplugs, and it comes up in the interface at
Zplugin>Mulidisplacement 2.You'll need to
restart Zbrush first for it to see these plugins. There are 3 buttons,
one for finding out how many segments the object
has, one for creating all the maps, overwriting any old ones, and one
for just creating new maps. The settings below those buttons are fairly
self explanatory, and then there's the Export Options.
Step 6: Exporter options
This panel is quite important for setting how the displacement images
are made, so there are a few things to note. Zbrush comes with a whole
array of presets, which will give different images. Each 3d package
handles displacements slightly differently, so you have to pick the
settings to match your package. Also, when you use a function which
uses the Displacement Exporter panel (you can use it in the Alpha panel
as well) when you export, Zbrush will export images for each preset
which has its status set to ON. These presets will be
in orange. For this tutorial I'm just going to be exporting one 16 bit
image for each section of my object, so I have my base LW exporter as
the only one on. Also, Zbrush converts the settings to a 'Quick' code
which you can see above, and if you want to share this with a friend,
you just type in the quick code and it will set up the preset for them.
The last part of the quick code is the name of the preset.
Anyway, the settings are as follows.
- Channels - determines whether 1 channel (greyscale) or 3
used for the texture. 1 is usually used for displacements, and 3 for
- Bits - no of bits per channel. Usually 16 for displacements
give better accuracy, and 8 for normal maps, though you can
to export 2x 8 bit maps from zbrush if your package doesn't load 16 bit
tifs, and make one be a major feature (like the hills on a mountain)
and the other to be minor features (like the rocks and boulders) This
should give you the same kind of resolution as 1 16 bit image. In LW
you'll need to set the minor map to have less of a displacement effect
than the major map (for example set the major map to 1m, and the minor
map to .02m or so). You
might only want to use 1 8 bit map if your high poly object isn't going
to be very complex.
- Vertical flip - You need to use this for LW since
it's UV's go up from 0 to 1, whilst Zbrushes go DOWN from 0 to 1.
- Scale - this performs a contrast function, to fit the
displacement best into the 16 bit range of the image. ADF sets where
the middle of this range is using the value in the
Alpha>AlphaDepthFactor setting. If you're using multi
displacements, this should be off. This is because the displacement
range of one map might be different to another (peaks might be higher
for example) and so the displacement values at the edges of the
textures will be different if ithis is on, even if the displacement is
the same. We turn it off to ensure the displacement at the edges
of the image give the same brightness values and minimise seams across
- Smooth - smooths the image slightly.
- Seamless - Calculates across the seams slightly so as
reduce seams on your final object's displacements. If your UV
borders are close together, you'll need to lower the Border setting in
the Multidisplacement 2 exporter. so zbrush doesn't over paint
a UV'd area.
- CH1/2/3 range - this tells Zbrush what part of the
to produce in this channel. For a LW displacement you set it to full,
which means both positive and negative displacements are put in this
- CH1/2/3 res - determines exactly what information Zbrush
that channel. You can choose full displacements, or major
displacements, minor, normal map +X/-X/+Y/-Y/etc information in your
channel. For a LW displacement map, we want the Full displacement in
just this one channel.
Step 7: Exporting to Lightwave
you've set up your exporter settings, and have just that exporter
turned on, you're almost ready to export. Switch down your subdivision
levels till you're at the base mesh again.You can't create displacement
maps till you're in this state. Finally, hit the Create All
button. A dialogue will come up allowing you to choose the base filename
for your displacement textures.
Step 8: Preparation in
we've done all that we need to do a little tweaking in LW. Since
you can't select which UV segment to use for a particular image, we
need to separate the Texture UV map we've already created, into the
head and body UV's. The quickest way to do this is to unweld (ctrl-u)
all the points of your object, then select the polygons of the two
halves of your body and Maps>General>Edit
Vertex map and give it a name like 1-bodyUV. You unweld first to avoid
any points which are shared by the head and body having their head UV's
copied over to the new map. Do the same for the head, calling it
2-headUV for example, and you should have two maps, one with all the
head polys on, and one with all the body polys on.
Merge your object back together, and turn it into a subpatch object.
Save it, and export it to Lightwave Layout.
First of all you're going to need two plugins. They are available here:
The Tiff loader is needed to load the images we have created, since LW
doesn't ship with a native 16 bit tiff loader. You can use the
Major/Minor 88 displacement saver types if you don't want to use this
loader, but it's free, so you might as well :)
The Normal Displacement plugin is a bit like the LW native Normal
Displacement plugin, but it quite a lot quicker, which is useful with
the amount of polys we'll be getting up to.
In the Properties panel for your object, add the plugin called
NormalDisplacement NOT Normal Displacement (with a space) as this is
the slow LW one.
Open up the interface of the plugin.
Most of the panel is fairly self explanatory. Vertex size controls
image antialiasing, you shouldn't really need to modify that. Cache
geometry speeds things up, but if you modify your object you may need
to turn this off and on again to update the displacement. Evaluate
doesn't apparently do anything due to a bug in LW. You can choose to use
the undisplaced mesh for the normal positions or use normals which have
been displaced by other plugins using the next toggle. Luminance centre
determines at what point in the brightness of the texture displacement
changes from in to out. I have it set to 50% grey here, the middle of
Step10: Set up your maps
Go into the Texture panel of the plugin.
Add two image textures, and load in both of the maps you have created
(Zbrush actually made 4 maps, one for each segment, but since I'm using
the same map for both left and right, I'll just need the two more
complex maps, since I only really drew on one half of the creature).
Select the corresponding UV map for that part of the creature, and
you'll have some thing like this:
Not terrible exciting is it? Well go into the Geometry tab of your
object's Properties panel, and push the Subdivisions up to 20 or so,
depending on how brave you're feeling.
Suddenly much better but a little slower! You can use the displacement
map as a bump map too, to get the finer details, or bump up the
subdivisions even higher if your pc is fast enough.