Texture Tutorial with Lothar
Ambient Occlusion Maps
Yesterday our tutor Lothar gave us an incredibly helpful
tutorial on UV mapping for textures with the main focus being around AMBIENT OCCLUSION MAPS
which
are used as a bas canvas upon which other textures can be applied. AMBIENT OCCLUSION MAPS mimic areas of
shadow, for example if you had a tyre underneath a mud guard on a vehicle then
you would want to bake on an AMBIENT OCCLUSION MAP in order for the
wheel to appear as though there is a shadow being cast from the mud guard. All
other textures applied over this in Photoshop will then have darker areas and
you will know where shadows need to be placed instead of randomly painting them
on without a clue.
I tried to keep up and write as detailed set of notes
and workflow as possible so I hope these make sense. I don’t have the time
right now to create and bake my own occlusion map but I will do when I get
round to texturing my museum study level.
.
Baked occlusion map: Black and white to create a shadow
upon an object. Adds very fine detail.
Shading: Hypershade > (Mental Ray) > surface
shader > select mesh > right click (either on object or hyper shade
surface shader square) > assign material to selection.
Mental ray (Hypershade) > ambient occlusion (mb.amb.oclusion) > move it next
to your surface shader in the Hypershade window > middle mouse drag white
occlusion onto surface shader (in the Hypershade window) > default >
double click ambient occlusion > (sample controls quality of “noise/texture”
the ambient occlusion gives) possibly make it a bit darker.
Back in perspective view > select rendering from top
left dropdown on shelf > lighting and shading > batch bake (mental ray)
> select square for options > “objects to bake” select the meshes you
want to bake on > use bake set override > colour mode to occlusion >
occlusion rays change the quality, the higher the number the higher the quality
> X & Y resolution 1024 (double the size of the texture you want to use
and dictates the size you want to use in photoshop) > convert and bake.
Using
the Ambient Occlusion Map in Photoshop for New Textures
To get a snapshot of your UV go to UV editor > polygons> UV snapshot
> change the resolution to what you set the ambient occlusion map to bake to
(i.e. 1024) > you can use JPEG for this > you should be left with the UV
lines from the texture editor.
Find the textures you want to use and ensure they are the same resolution
as your ambient occlusion map > open ambient occlusion map and textures in photoshop.
Drag the UV lines (in photoshop) onto the ambient occlusion so that you get 2 layers in photoshop > ensure that the UV lines place
perfectly over the ambient occlusion map > unlock the bottom layer and re
name.
Create new layer > name it base > re colour it a neutral grey colour
(avoid strong saturated colours like black and white) > ensure it is at the
bottom of all the other layers > drag your texture onto your main file (this
will become the 4th layer) > put it above the grey
layer > rename > select ambient occlusion map > use the drop down menu
under the layers and select multiply.
Now you can mess around with the settings on the texture layer (lighten,
darken, saturate etc etc) > don’t edit the UV layers and do not flatten the image!
Now you save it > save as > save as a Tiff > name it appropriately.
Hypershade editor
> Blinn (used to simulate general surface textures such as wood, metal,
glass; you can edit the transparency) > middle click drag the Blinn onto the
mesh you want to work on > double click Blinn shader > under colour
select options > file > find the ambient occlusion texture image you just
created in Photoshop.
If you want to make
certain parts of your mesh a different texture to other parts (for example, the
rubber ring around the tyre needs to be a rubber texture and the wheel needs to
be a metal) you can select the different parts on the UV lines layer in Photoshop > grab the texture
you want the selected parts to be > place the texture underneath the UV
lines.
You can create new
layers > select a colour > paint over the edges so that the different
parts of the mesh blend (between the tyre and the metal).
Specular
Map Time (shine & matt)
Back on Photoshop (with the ambient
occlusion map open) > create new group under layers > call it diffuse
> select all layers bar UV lines and put them under the group.
New group > call
it specular > re-save this as a jpeg > make it black and white >
increase the contrast (optional) > once you have painted over the new jpeg
you can drag it under specular on the TIFF file. (The more white you draw the
shinier the object becomes).
Back to Maya >
once you have double clicked specular map on the Hypershade window > under
specular > colour > select the options to enable you to choose a file
> choose the TIFF file with the new specular paint over.
TIP: For different
types of map (such as reflective and specular) you start in Photoshop, paint on the effect
over the UV map then apply it through Maya.
I will be going into more detail with screen shots and examples of my own work but I am not at this stage yet in my work, I also need to pick the asset that I am going to texture, un wrap the UV's, organise them, find textures, THEN sort out the UV maps. Im scared and excited all at the same time :P
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