The Making of The Frog 2


Some notes about my work on this short movie



Author: David, created in: 2004, last updated in: April 2010
Welcome to the “making of the Frog 2” pages. Here are some tips, techniques and explanations about the work for this short movie. I’ll also explain some mistakes I’ve done and how I untangled them. The last pages tell how the idea of this animation started. This is not really a tutorial, but a report about this production. I hope you’ll find this useful.



frog2_buildmodelThe references for the modeling were some photos that I got from the internet. It was not easy to realize the scales of the body, as the red eye tree frog always goes into twisted positions. As for the head, I had to widen the size of the eyes in the second version to get something closer to reality.
This is an early modeling stage. On the foreground of the image is a subdivision created from the low poly modeling (background).

frog2_buildcaptureAnd here is what I got after some days of work. When I first designed the frog, I didn’t intend to animate it. “The Frog 1” was just a modeling and texturing project. The way it was modeled was fine if it had to walk on all fours only. But my next project with the frog needed him to stand up. So I tried to enveloppe this mesh as it was. But when he is standing, the skeleton was twisting the mesh in a awkward way. So I had to re-model the frog standing up. The rig had to be modified as well.




A global view of the first version of the frog. The texture supports are installed as I start to texture the mesh.
Texture Editor job: when I started to unfold the UV’s on this frog, I was a beginer with this technique. So my goal was to unfold the mesh with as few cuts as possible. As you can see, the frog in the T.E. now looks like he’s been squashed under a truck! Of course, this method was a mistake. Keeping all the polygons attached to each other makes you distort those polygons. At the end, the polygons in the T.E. were so deformed that the texture looked too much stretched on several faces.
I had to modify the organization of the UV’s in a second attempt at UV’s unfolding.


frog2_textuv02This is the final setting in the Texture Editor. Now the UV’s are less distorted. Note that even with this new UV set, I experienced some distortions with the texture. For the next character I UVed, I cut even more parts than what you see in the above picture.
The key to a good texture editor work is not trying to keep all your polygons attached. You should avoid distortion as much as possible.
There are different ways to keep texture and color consistant across seams. One of them is to cut parts of the mesh where the colors looks solid. Another evidence : you should cut parts of your mesh where a seam is undeniably visible.
Also, it is generally a good idea to cut along a mesh joint. Indeed, as the skin of the character folds, the texture’s seam will be hidden inside the folding. If a joint is often wide open and is never hidden inside a folding, you will need to cheat in Photoshop so that the seam does not show any texture roughness. This texture’s seam will be sourrounded by plain color. On the edges of the seam, this plain color will gradually be mixed into the asperities of the texture.
If this effect shows up in the final texturing, fear not, it will never be noticeable in the final animation, while the character moves, is under the effect of motion blur, and so on.

There are also some advanced techniques to hide the seams, such as creating a fade effect on the textures on the areas of the seams, but this would need another article.
This is a render of an early texturing stage. At first I just wanted to paint on the mesh some colored areas, so I could get a 2D pattern that I would complete in Photoshop, filling it with textures.


Painting the body

At that time, I didn’t have much experience with 3d painting softwares like Deep Paint 3D, as for Zbrush, I’m not sure version 1 existed. So the process for paitning the frog’s body was a bit tedious. I was obliged to use this workflow :
1: Check photos of red eye tree frogs to see how the colors were assigned on its body.
2: Select points in XSI’s 3d view along the limits of the color I was interested in. Each colors one by one had to be grasped.
3: Display XSI’s texture editor with the samples selected in red.
4: Switch to Photoshop and display a layer with a screen shot of the same texture editor as in XSI.
5: In Photoshop, locate the samples shown in red in XSI.
6: Paint colors (no textures at this stage) on those polygons, thus delimiting the different parts. The Photoshop brush was affecting another layer with an opacity of 50%.
The same process had to be done for each colors, each side of the frog. A very long task. Hopefully, my use of Zbrush on following projects has made things easier.
I finally managed to get this template in Photoshop. This pic shows an early stage of the work I’ve done in the 2D software. Only the colors are defined for now. I then proceeded to add some detailed textures.
The final Photoshop texturing work can be seen here. To achieve this work, parts of photos have been pasted then mixed together and re-arranged. Although I spent a lot of time on this texturing, I enjoyed it!
Going ahead with the application of the global texture map on the mesh.

This is the final texturing of the frog.

The bump map for this frog. All manually painted in Photoshop.


The frog viewed from below, with its bump map applied.

Farther view of the frog from below.

For the eyes of the frog, I also re-used some photos as a base, then did some painting.

This is a WIP, almost final render, when I was at the lighting stage.


More production notes

Looking for information and photos of red eyes tree frog, I got interested in this creature. You can check my summary on this subject.

The guys at 3dvf had a visit from a frog in their office. As they knew I was working on a frog, they sent me a lot of photos they took from this charming gentleman.

While this frog was visually very interesting, I didn’t use it as a reference for the red eyed tree frog, as the french frog’s skin didn’t look like the South American’s one. However, it could be a very good reference for Zbrush fanatics.

This picture show a sub surface scattering test. I did it for the Tom Sporer tutorial. SSS could have been usefull for the frog. Indeed, the frog has a very thin skin, and on some parts of his body, it looks semi transparent. Its fingers, for example, have this translucent feature. It could be possible to build a map that would reveal SSS effects on parts of his body. And perhaps attach lights to the skeleton.
Anyway, I found out about this technique after the short movie was completed, so I’ll keep it in mind for another creature with a transparent skin.
Now, cheating is not necessary to achive an SSS look, as it is integrated in Mental Ray



This is one of the rigs I used in the animation.

Testing the skinning (envelopping) of the frog by moving the rig’s control objects.

One of the animation challenge was to have the frog walking on an uneven surface. Chek my tutorial explaining this subject.

frog2_previewclimbing video link

Another animation challenge: having the frog climb a plant, while the plant is moving, and having the hands and feet fixed on the moving branches.
On the Xsi Lounge forum (now defunct), a guy asked me how do these branches react to the weight of the frog legs, and asked if soft bodies have been used. In fact, everything is manually keyframed. I also animated the constraints.
First, I animated a rough animation of the climbing forg on this plant, and at the begining, the plant wasn’t animated. Then I keyframed the animation of the plant, like if they were reacting to the weight of the hands and feet. In a third animation pass, I modified the animation of the frog so its limbs would almost stick to the moving branches. Finally, I added some pose constraints so that the sticking of the hands on the plant was more efficient. These constraints were animated to let the hands go from one branch to another.

This picture was useful for the synoptic view.
The trick I used to keep the dances synchronized with the music was this 3d volume meter. When the snare drum was bursting, the yellow object was up. And when the bass drum was audible, the red object was up. This way I had a good visual reference for the music and adjusted the frog’s dance on it. To animate those kind of objects, you should try to find a nice “sound to curves” script.



I thought break dancing would match the frog’s personality. So I started to look for some cool breakdance tunes and video clips. One of the break dancing videos had a Freestylers song on it. This song “Freestyle Noize” became the dances’ theme.
Freestyler’s record label “Fresh Music” kindly gave me permission to use this track in my short movie.



Working on “The Frog 2” has been a valuable self teaching experience. Thanks for reading this article.

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