Sculpt photoreal amphibians

3D artist, Jeremy Celeste gives us a rundown of the key techniques he uses in the creation of his photorealistic frog image, Look at Me...

First steps

Look At Me was a challenging project in many ways. I wanted to make a macro photography shot of a dark frog in a green environment, so I took many references to hone my choices for the design, aspects and environment I wanted for it. I also gathered some anatomy references and started to work in my favorite modeling software; .

The modeling process at different stages

The modeling process at different stages

Rendering and shading

Once the modeling was done, I started on the layouts in Maya and began my favorite part of the process: rendering. Lighting for this project was done using a forest HDRI plus a Sun light. I started my Lookdev work with the frog and, once I was happy with lighting, I started to work on the shading.

HDRI used for lighting in combination with the sun light

HDRI used for lighting in combination with the sun light

Creating a convincing texture

As a Lighting/Lookdev artist, my main concern was the sticky texture of the frog. This was important, not only in the overall aspect because it could easily look like plastic with a lack of detail, but also in depth using micro bump to break specular and add variation.

The tip was to add two speculars, one soft and another very tight. This creates a nice effect, but it only works if the model has enough detail, otherwise it will look too shiny/plastic.

This image shows the micro bump used to break specular and add variation to the shader.
Credit: http://gl.ict.usc.edu/Research/Microgeometry/ for the base texture

Refining the texture

The second part of the shading work was to add sub-surface scattering (SSS) with a front and back scatter layer to make the skin soft and add some depth variation.

Once I was happy with the shader, I made some render tests both close to the frog and further away to see the overall quality of my model and shader.

The trick to get wet-effect eyes was to build a liquid shape around the eyes and assign a water-like shader to it. This added the tiny but very important specular which made the head and eye fit together realistically.

Refining the textures and shaders to create a realistic effect

Refining the textures and shaders to create a realistic effect

The background

The next step was to manually place a few planes on the ground, which, using a cutout map, became leaves.

The trick to creating realistic leaves is to use a double-sided material, and make the front opaque and the back translucent. Using translucency on the back-face gives the look of a real leaf and is very cheap and easy to setup.

Leaf textures from www.cgtextures.com

Leaf textures from www.cgtextures.com

Adding the detail

After the overall scene was done, I added hundreds of mud/rock-like shapes on top of the ground and leaves. By using this technique, we give the impression that this frog is in a real place. You'll find that more detail in a scene makes the atmosphere more believable.

I also added some flies around the frog. These are motion-blurred at the end to give an impression of movement, which is very important for dynamic.

This image shows the finished layout, with all the geometry

This image shows the finished layout, with all the geometry

Finishing touches

Finally, I added more effects on the scene, such as grain and other cool stuff, to finish this image. I also focused on the grading – in other words, adding color variation/mood to the scene from the raw image.

I only used the beauty render for the compositing. DOF and motion blur were rendered directly in order to be as accurate as possible.

The final render

The final render

Related links

See more of Jeremy's work on his site
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