Blended Cube Projection In
3dsmax By Neil Blevins Created On: Feb 12th 2013 Updated On: Dec 9th 2024 Software: 3dsmax First off, I recommend reading my Blended Box
Mapping tutorial first, it contains useful background info that
will help you with this tutorial.
What is a Blended Cube
Projection?
Say you have a complex object, like a robot head made up of 291
objects, and you want to paint some specific dirt on it, like dirt
near the places where the screws intersect with the face shields, drips
traveling down the face, darkening near panel lines, etc. Some
possibilities...
You could uv
the objects and then use a 3d paint program, but damn, uv mapping 291
objects is a real pain.
You could auto map it, but the result will be
useless if you want to edit the textures in photoshop.
You could use Ptex, but then you'll have to keep track of 291
Ptex files associated with this model.
You could use
procedurals, but it might be a
lot of work getting it to look natural when it would be pretty easy to
paint.
The Blended
Box
Mapping technique works great for applying "General" dirt to a
surface, but you want control over placing the dirt in very specific
spots.
If you want to apply "Specific" dirt to a surface, you
need to take the next step, a Blended Cube Projection. This is very
similar to a Blended Box Map, except instead of using a single map
aplied to all 6 sides, you
create 6 different maps, one for each direction, and then apply them to
your surface.
The basic procedure is as follows, start with your model...
Assign a Blended Cube Projection.
Render Templates of your objects from all 6 sides.
Now open Photoshop, and load the front image. Create a new layer, and
start painting a dark brown color everywhere you want dirt.
Save this as a psd file, so you can always go back to your working file.
Once done, click "Lock Transparent Pixels" in your layers palette on
your dirt layer, and then fill your layer with white. Now everywhere
you painted brown will be white. Then place a black layer below the
dirt layer. And flatten the image. Now you have a black and white mask,
where white will put dirt, and black will be transparent. Save this
mask as a tif.
Open up max again, go to your Blended Cube Projection map, drop the
dirt bitmap you just created in the front slot.
Now place your Blended Cube Projection map in the mask slot of a Blend
material, with
Material 1 being your metal material, and Material 2 being a dirt
material.
Hit render, and voila, your dirt details are now projected on the front
surfaces of your objects.
Repeat for the other 5 sides, and now you've placed specific texture
details on all of your objects quickly and efficiently without the need
to unwrap everything.
3dsmax BlendedBoxMap Example
The best and most modern Blended Cube Projection
technique is using the
BlendedBoxMap inside 3dsmax that was released in version 2017 Ext 1. If
you turn it from using 1 or 3
projections to 6, you are now using it as a Blended Cube Projection
instead of a Blended Box Map.
Here's a video showing the process...
3dsmax SoulburnScripts Blended Cube
Projection Example
This is an older technique that I don't recommend using anymore, but
I've included it here for historical purposes.
Take the robot head model with the simple metal
material applied to it. Select all of the objects.
Now make sure all 6 maps are empty (since we haven't painted the maps
yet), and hit Do. Now we have 6 cameras pointing at our object from all
6
cardinal directions, Up, Down, Left, Right, Front, Back.
And we'll have 6 Planar
UV modifiers aligned with the cameras.
We also have a mix map in the medit that uses all our cameras...
Next, we use another soulburn script, this one is called
cameraMapTemplateRenderer. Here's the interface...
Change the Mode in the cameraMapTemplateRenderer to Selected Cameras,
and
select your 6 cameras. Next, it's recommended you
turn on camera lights, so you get
even illumination from all camera angles. Or for even better results,
turn off all lights except a dome light (for example, use vray's "GI
Environment" light set to a multiplier of 1 and a color of white in the
render dialog if you're using vray as your renderer). Finally, in the
script's interface, choose an output directory and hit Do.
You'll now have 6 templates saved to you directory.
Now open Photoshop, and load the front image, and create the dirt layer
are discussed in the section "What is a Blended Cube Projection".
Open up max again, go to the map tree that the
BlendedCubeProjectionMaker script created, and load
your new front bitmap in the appropriate map.
Now place your map tree in the mask slot of a Blend material, with
Material 1 being your metal material, and Material 2 being a dirt
material (this doesn't have to be complex, a standard material with no
specular and a dark brown color for instance).
Now hit render. And voila, you have painted dirt on your model. Do the
same for the other 5 directions.
Here's a video showing me apply a blended cube projection using the
SoulburnScripts UVWMapping Technique to a robot head...
Conclusion
So the big advantages of using a Blended Cube Projection instead of
unwrapping / ptex / procedurals are...
You were able to apply dirt to a whole
bunch of objects without the need to worry about unwrapping the UVs on
every object.
If you need to move or add to or modify the faces on any of your
objects, you can do so without
messing up your paint or uvs.
You have 6 images to
manage, as opposed to possibly hundreds of images necessary for an
unwrapped object.
Frequently I'll start by making a material that uses a Blended Box
Map, just to get the basic patterns on the object, then I'll use a
Blended Cube Projection to add more specific details on top. For those
of you who do Matte Painting, you'll recognize this
technique, it's just it's being used to do regular shading as opposed
to being used to do more traditional Matte Painting from the hero
camera.
Anyways, hope you see the advantages of the Blended Cube Projection
technique and give it a
shot. You may never unwrap the UVs on another object again!
