Making Of 'Traditional Toad clay sculpture in CG'

Jin Hao Villa covers the general software and sculpting processes used in the creation of his image, covering workflows using ZBrush SpotLight and Softimage.

In this tutorial, I will go over my process of sculpting a realistic toad inside ZBrush. I will show you the brushes I use, and the tips and techniques I was mindful of in the development of my sculpture. Afterwards, I will take the model into KeyShot and show you my materials and light setup over there. I'll also show how I composited my passes in order to achieve the most realistic result possible.

This toad model actually started as just another simple exercise to educate myself more about animal anatomy. At first it was only going to be a head bust, but somewhere down the middle of my sculpting exercise, my creativity and imagination got the best of me and I decided I would chuck an armature in there and mimic an actual real life clay model in the process of development.

First off, it is important to gather references of your subject. I had a look at many kinds of toad species on the internet. The one I admired the most was the ‘cane toad' and decided that that was what I was going to sculpt. Apart from looking at Google for references, I would also highly recommend the BBC nature collection, arkive and gaping maws.

Loading references

Once I gathered my references together, I picked the main 3 that would represent the front, side and back view of the toad and loaded those into SpotLight. The rest of the other references were loaded in XnView and placed and stacked across my 2 other extra monitors. ZBrush was loaded in my main monitor.

The first thing I did was load my reference image as a texture in ZBrush, then afterwards I loaded it into SpotLight by pressing Add to SpotLight. Once loaded, I used the spotlight panel widget to resize my reference image, making sure to decrease the Opacity so I could align the model to see how closely it matches the reference.

I then made sure I set my spotlight radius to 0, otherwise when I pressed Shift+ Z to go back into edit mode, my reference image would not have correctly dropped into the canvas and I would have ended up with a transparent brush cursor that resembles a stamp of the reference image underneath instead. If that happened, I could always press Shift+Z again to hide/unhide the reference image, while pressing just Z to enlarge the Spotlight widget.

Loading my reference images into ZBrush as a texture

"Make sure that when you DynaMesh, you do so at a fairly low resolution; this way you don't end up with too much topology that would make pulling forms around that much harder to do"

Sculpting the toad

I started off using a ZSphere rig, and when I got to a ZSphere armature I was happy with, I then pressed Make Adaptive Skin and then Make PolyMesh 3D. From there I began pulling shapes together until it resembled the appearance of a toad, DynaMeshing each time I felt the topology was not enough and getting stretched.

Make sure that when you DynaMesh, you do so at a fairly low resolution; this way you don't end up with too much topology that would make pulling forms around that much harder to do. When I sculpt I also like to use the basic material with a bit of gloss to the Specular highlight and have a Bounce light added into my light rig to properly evaluate how all the forms are looking. The brushes I mainly used at this stage were the Claybuildup, Claytubes and Move tools.

Sculpting the toad in ZBrush using the Claybuildup, Claytubes and Move tools

Refining the forms

Once I was happy with the basic shape, I then started refining the forms more until it got to a stage where I was happy with it, and I wasn't really going to change the silhouette that much anymore.

One technique I used in my process was applying the sketch shader that I created to see how my model looked if it were a 2D drawing. This really removed my focus on the details and forms for a while, so I could solely evaluate just the rhythms and silhouette of my sculpt from all angles.

Download the sketch shader asset

Afterwards I decided it was time for a cleaner mesh, for sculpting the last pass of details and form refinement onto. I must also mention I wasn't concerned too much about the topology being animatable – it just needed to be good enough to sculpt clean forms out of. For this task I used the powerful built-in ZRemesher. It popped out the kind of mesh topology I needed in less than a minute.

Refining the sculpt and using the sketch shader to assess the fluidity of the piece

Detail

The next stage was the detail tertiary pass. I decided the top half of the toad would look completed and be refined to have sculptural texture detail like a real toad would, while the bottom half would be in the middle of refinement, purposely left incomplete with strips of clay and tool imprints still showing through like a real life clay sculpture would. To get this look right, I gathered some references of actual clay models in production by traditional sculptors. I look up to artists like Aris Kolokontes and Simon Lee.

In the image, you'll see all the brushes I used to help me get this look right, and the Alphas I used on the more refined upper part of the toad. For the Crease brush, you can download it for free here.

Diagram showing all the brushes I used in creating the detail on the toad

Armature

The armature was simply modeled from a reference image I grabbed off Google, though I decided to imprint my own name on its grip as sort of an artist's signature!

For this hard-surface model, I simply did it in my preferred modeling application XSI using curve modeling tools. For the coil around the armature, I used the topology curve in ZBrush and then inserted a curvetube along that curve.

The armature and coils around it in XSI

Polygrouping and exporting

Once everything was completed, I began polygrouping my models where each polygroup ID meant a specific material was going to be used just for it. I then exported the entire model scene, and imported the file into KeyShot with the Group setting on in the import settings.

Exporting from ZBrush into KeyShot

Texturing

I then applied a different material for each PolyGroup ID. Take note that I did not UV any of the models except for the board, but did use box mapping inside of KeyShot to procedurally texture my non-UV-ed models.

Some of my texture settings for my model

"I used a sepia photo filter to harmonize the colors of the scene and then used a lens correction filter to quickly add Vignetting and chromatic aberration"

Rendering passes

I then rendered multiple passes for my toad (Translucency, Glossy Specular, AO) and composited it all in Photoshop playing around with layer modes and masking off where I wanted the pass applied.

Once I was happy with the result, I used a sepia photo filter to harmonize the colors of the scene and then used a lens correction filter to quickly add Vignetting and chromatic aberration to my final image, which added the icing to the cake.

The various passes rendered from my model

Top tip 1: Gather plenty of references

Make sure to gather a lot of references early on. This is to ensure you understand what you are modeling in a three-dimensional view and prevents you guessing the forms and anatomy of your subject. You will also use those same references to tweak your shaders so they come out as realistically correct as possible.

Top tip 2: Start with the basic form first

Always start off by working with primary forms first, then make your way to secondary forms and then tertiary details while increasing the resolution of your model as you go along.

Top tip 3: Keep an eye on the silhouette

Pay just as much attention to the rhythms, flow and silhouette of your model as you would with the forms, anatomy and detail. Remember a nicely-shaped model with a strong silhouette is better than a poor ambiguously-shaped but elaborately detailed one.

Top tip 4: Good lighting is key

For rendering, make sure to nail your lighting down first, so your model already looks good in the shaded view. Afterwards you can work on your shaders, testing them out on simple objects first rather than spending a great deal of time experimenting with them on your final model.

Related links
Check out Jin Hao Villa's website
For the Crease brush, and other useful info, click here
Don't just rely on Google for references, check out these:
BBC nature collection
Arkive
Gaping maws