Texturing for 3D – fruit bowl project



Through exploration and testing, I came up with a pipeline that exploits my skills in photoshop and highlights the 3D paint tools of mudbox. That workflow looks like this-

• Step 1/ collect reference and also use the reference photos supplied to analyze the various fruits – make some decisions about what the fruit should look like
• Step 2/ create several stamps in photoshop for each fruit that will be used as stamps in mudbox- these stamps will be either of the following-

a/ what I will refer to as ‘transparent white stamps’ – these will be white colour with transparent background. They will be made by either hand painting or extraction from photos and they will contain textural information, not colour. They will be 16 bit tiff files saved with transparency. In Mudbox, they will be loaded as stamps and used to paint diffuse colour using colours selected with the mudbox colour picker. Randomise and stamp spacing can be utilized to avoid repeating patterns.

b/ what I will refer to ‘projection stamps’ – these will contain colour information, they will be tileable, and will not contain transparency. These will be used with the projection brush in Mudbox using the colour information that is ‘baked in’ in photoshop. They will be very simple and mainly used for diffuse as ‘base layers’ – just a simple texture pattern to spray onto the fruit so that I am not starting with flat colour.

• Step 3/ Geometry – Each fruit piece will be exported as an obj file from maya to open in mudbox. That model will be subdivded a few times in mudbox so that I have a nice smooth model to paint on.

• Step 4/ Mudbox painting – using numerous diffuse layers, firstly using the projection stamps, then progressing on to transparent stamps. I expect to end up with about 5 or 6 diffuse layers working from the base up like an oil painting with the finer details at the top of the layer stack.
I will only paint diffuse in mudbox and leave bump and reflection for photoshop.

• Step 5/ Once I am happy with my diffuse painting, I will export to PSDs retaining all the layers. I can now manipulate this painted information in photoshop. I play with the opacity of layers, the stacking order, and use PS’s colour correction tools until the diffuse looks just right. The aim is to have no ‘baked in’ lighting information – just flatly lit images with plenty of texture detail.
I pack all the layers into a layer set and name it ‘diffuse’.

• Step 6/ Now I duplicate the layer set twice, rename the sets to ‘spec’ and ‘bump’ and start to manipulate the layers to work as reflection (specular) and bump. In most cases I desaturate each layer and in the case of specular I dramatically increase the contrast. Sometimes I remove layers alltogether if I don’t want them to contribute to the spec or bump. Each case is very different.
I find that using the diffuse information and re-working it for spec and bump avoids having to do more painting than you need to. Also, all the various maps then ‘fit’ each other and it leads to a more pleasing unified result. It does mean that you have to know what you are looking it, because unlike Mudbox, Photoshop can not really ‘preview’ the other maps.

• Step 7/ – I keep this layer structure on a master PSD file, then flatten each set and save it out as either iff format in the case of colour maps and greyscale tiff in the case of black and white.
Now I can load the maps to their respective mia x shaders in maya.

There will obviously be be some test renders a re-tweaks back in photoshop, but this is essentially the process. It sounds complex but when on a roll it can all happen quite quickly.

Now I will show showcase and discuss some of my particular results. I will talk about the orange first because this is the only one the strayed a little away from the above pipeline.

The reason this one was a little different from the others is that most of the aesthetics of an orange come from the bumpy surface. So in this case I actually sculpted bump detail  in mudbox and extracted a normal map. Here are is the layers for the sculpt, the first is a level 4 sculpt I called ‘lumpy’, the second and third layers are higher freq level 6 sculpts of the ‘pits’ and the ‘fractals’ –

For the apple, I used the pipeline outined at the top of this post.
Here are the various stages –
Tileable projection image made in photoshop to be used with the projection brush in Mudbox – mainly just for the base layer of diffuse-
For transparent stamps , a common method was to photograph the fruit, capture areas of texture with tools like ‘colour range’ –

then using brushes and warping tools, straighten things out and simplify details for a final stamp image that looks more like this (I have inverted the colour on this stamp so we can see it here, but ordinarily the colour area is white)

then I would use this in Mudbox to start adding detail on a new diffuse layer-
when the diffuse painting was complete, I would export all layers to photoshop and start manipulating. By keeping diffuse on seperate layers, I could make decision like isolating the spots to only the darker red areas of the apple skin with some simple masking in photoshop.
and I keep everything on layers in a master texture file so that I can manipulate things more once I start seeing some test renders-

Same process for the pear, painting textures in Mudbox –
then manipulated in photoshop, to create the following maps –
You will notice in the above case, how the seperate diffuse layers are invaluable for making the spec and bump. In mudbox, I painted the brown at the top of the pear on its own layer because I knew I would want to isolate it from the spec – no probs, just fill that layer with black on the spec map.

Same process
for the banana.
Making some stamps –
bananaStamp bananaStamp2

Painting the diffuse layers in mudbox-
then manipulating in photoshop to create the following maps –

The biggest to task in texturing
the wooden basket was redoing the UV map. I figured out that the key to making it look realistic was to capture the laminates on the side walls. To achieve this, I needed to re-lay out the UV’s. I also wanted to see how the ‘UV layout’ software worked for man-made objects since I had only mapped a character in there before. So I used the UV space like this –
I just used a simple balsa wood texture that I already had, but the key was to make darkened ‘laminate’ strips as shown in this detail shot-
I did this by darkening inside of thin selections that I applied a ‘wave distortion’ filter to, to break it up and make it look more ‘wood grainy’. Probably massive overkill, but I was having fun 🙂

I will talk about the grapes, glass, benchtop and tiles more in the rendering part as they were procedural.


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