Making Of 'Barack Obama'

Introduction

Hi, my name is Toni and I am going to walk you through the process of making a digital portrait.
Making a digital portrait can be a very difficult task if not prepared well, so my first advice would be to get a lot of references for your project.

Since my project was related to a well known public person, finding good references was an easy task. Having said that, it was impossible to find images that could be useful for assembling good image plains and so I relied mostly on eyeballing techniques.

With all my personal projects I try to learn as much as I can, so I often change pipelines and workflows as well. Don't be afraid to try some new techniques and applications. Technology is growing every day, giving us the opportunity to work more efficiently.

In this project I switched between Maya, ZBrush, Silo, UV layout and Photoshop.

Base Mesh

The first thing I did was build a simple base mesh in Silo using smoothed cube primitives and extruding a few faces from the bottom to make neck volume and shoulders (Fig.01). 

Fig. 01

Then I imported the base mesh as an obj file into ZBrush and started sculpting. In this stage I was focused on the overall shape and volume of the model; I was not so concerned with likeness features.  My goal was to make good human bust sculpt and build new topology over that high res sculpt. That way I could have a more efficient edge flow for further sculpting (Fig.02).

Fig. 02

When it comes to remeshing your sculpt there are many good solutions. I could have used ZBrush Z-Spheres, or even Topogun, but I decided to do it in Silo which also had some nice tools for that task.

After laying down new topology I quickly realigned my base mesh with reference images by using the move brush in Silo. After half an hour of pushing and pulling I had a good base mesh with a decent percent of likeness that I knew I could further refine in ZBrush (Fig.03).

Fig. 03

In the sculpting process the mesh can be deformed behind the point where your polygons align with distortion free UVs, which is something that will need fixing. I often do the UV part before adding more details to the mesh and for this task I use the great application called UV layout. With this sculpt I didn't spend much time on UVs at this point because I knew I would be revisiting the problem after completing the model.

For a well-trained artist, the task of building a base mesh in such way can take between 1-2 hours. This mesh can then be used in lots of other projects because it will have good mesh structure and volume.

Sculpting

After building the base mesh I imported this new base into ZBrush for further refining and sculpting.  At this point I always think it's important to focus on the overall shape and volume of the model instead of the fine details. Both the overall shape and details are equally important, but at this first stage I suggest you to stay at lover subdivision levels and  make good use of every edge and polygon before stepping up to a higher level.

Also, don't forget to use references images at all times. If you are not the happy owner of two monitors then it is helpful to print those images out.

Sculpting in ZBrush is really fun, but be careful not to get too carried away and remember to check proportions of your model often!

After completing my sculpture I exported the model at a lower subdivison level and, once again, checked my UVs in UV layout. Then I imported that mesh into ZBrush again. That gave me I completed sculpture, with a distortion free UV layout, which was ready for texturing (Fig.04).

Fig. 04

Texturing

For the texturing part I used texture projecting techniques. Many people think that ZBrush can only paint on polys, but by using projection master you can actually project your painting directly onto the texture. For my model I used 4k sized textures.

Here is quick explanation of the workflow using this technique:

• Make a new document in ZBrush and resize it to the texture size or more
• Load the model and drop it onto the canvas, than press "T" to get in to edit mode.
• Once in editing mode, position the model to camera in the direction that you want your projection to be
• Make a new texture any size you want, for example 4096 x 4096
• Press "G" to enter projection master and choose the color projection with no fade option and press drop down
• Now go to Zapp link, which will transfer your canvas to Photoshop
• Now you can overlay a photo reference over your ZBrush model and realign the facial features of your photo to match your model. I find the liquefy tool in Photoshop most useful for that task.
• For more tips about Zapplink check out: www.zbrushcentral.com
• After saving your Photoshop work, go back to ZBrush and your texture will be projected onto the ZBrush canvas over your model, exactly as you made it in Photoshop
• Because you are now in projection master, press G again to pick up your projection
• After a couple of seconds your projection will be baked onto your texture
• Repeat this process a few more times, but with different angles and save those textures as different files. Now you can stitch those projections together in Photoshop.

From the basic color texture I made six different textures such as epidermal , subdermal , specular, bump and so on (Fig.05).

Fig. 05

The scale of the model one of the important things that must be well tuned, because subsurface scattering weights relies on the scale of your model. If you are not sure how to adjust the scale of your model in Maya or Max here is tip:

• First load your model and apply the sss fast skin material to it
• Place some point light in front of your model and one point light behind your model
• The point light that's behind should shine through your model in a red color when rendered. That red color comes from the back scatter component of the sss fast skin shader.
• Now adjust the scale of your model, or even better, the scale conversion parameter in material, until that red color only shines through the ears of your model
• That way you will be sure that your scale is correct since the sss fast skin shader comes already tuned for optimal results

My scale test can be seen in Fig.06.

Fig. 06

Hair

For the short hair, I use Maya fur. I don't have any particular tips for using Maya Fur; the only thing I would say is that when you test the fur be sure to turn of all the shadows because it can take a long time to render - especially with raytracing shadows.

Here is my hair setup (Fig.07).

Fig. 07

Lighting and Rendering

For the final rendering I used a high density mesh since I was still working on the image and didn't care if model was animatable or not.

The rendering is the part that I find the most time consuming because it takes a lot of test to come up with good relations between lights and shaders. Every test I did took between 3 - 15 minutes.

For the lights I used four lights. Two back lights were colorised; one slightly blue and the other yellow. The main key light came from the side and above and I had one big area light in front of the model for the key light. I set two area lights that were not illuminating the scene, but were only visible in the reflections of the eyes.

All of the lights in my setup were area lights because they produce nice soft shadows, but at the cost of more render time (Fig.08).

Fig. 08

I hope you have enjoyed this Making Of. For any further explanations, please feel free to contact me.