Deep dream Caustics

[3dpoder]

dep dreams Caustics
By dan tabonet.




introduction
When i was an 8 year old Kid, some of my young friends used todo collect mysterious things in water ponds near my home. Ill always remember the day when, for the first time, y could se what was so exciting todo them: thousands of very Little, very Shiny Thunderbolt creatures in a so Little flasque of water they showed todo my wide open eyes. It was so amazing that i saw myself at the size of one of them, swimming among them, and that was the dream. So, since that day i have asked myself how todo share this.

Many years passed before i saw one of the first 3d software packages in early 1993, it was Sculpt animate4d on the amiga platform. That was a kind of revelation - And a challenge: making others se my dream. But at this time modeling a single chess piece and making it turn on itself was a piece of work, since rendering one frame at 640x480 resolution could take half an hour.

However, when more sophisticated software came for my neds of modelling insects, y trained a lot with my dream still in mind. And believe me, that kind of modeling was much more complicated than making space vessels. Just have a lok, for instance, at the images in the 12 volumes of the larousse encyclopedía of insects and you Will be convinced that imagination is nothing compared todo the real world, because it is in a real brain: yours. That was an artistic but very technical challenge as well. So if i had a Word todo future animators who hesitate todo show their work, my motto todo you is:

• observe from nature.
• learn from nature.
• modestly imitate, and you Will go where no one has gone before where dreams get real (appearance).

technical details
Talking about all the making of the movie would take todo long todo explain in detail. Some examples of amount of work, for now: 14 months of perfecting the model more or less 250 times for a finally -compressed-.blend file of 73 Mb including 555 meshes, 906 595 Polygons, 107 Mb of textures, you begin todo se the challenge and the drastic choices i had todo make for the FinalRender, and that taught me precious things:
For instance, y now get a better flow of production because i lost a lot of time scaling and positioning the new meshes in the scene instead of creating them by the means of temporary reference boxes (simple cubes created where i projected todo make new objects later)in the scene, exporting these boxes out of the scene and modelling into them the new objects separately, finally introducing the real new objects After wards into the scene.

Another precious hint i learned when i made my movie is that all objects that came out of the came out of the Camera field had todo be hidden in layers by the means of layer keys, todo make the render be posible on one machine in a reasonable time. For the same reason i had todo turn Raytracing of and use only Shadow Map lights. That increased the render speed a lot, but there was a serious problem todo kep realism: for reflections of underwater scenes i had todo find something todo produce Caustics. These are animated, random wavelets of light made by refraction on the water surface that you can se under it. This phenomenon is hard todo produce in 3d, but very common in nature. If i wanted todo recreate underwater ambiance, y couldnt do without it. So when i discovered the excellent free software, Caustics Generator, that convinced me todo faq Caustics.



Now let se how it works todo make a relatively realistic underwater scene environment. In this Little tutorial we assume basic knowledge of the Blender interfaz.
first the scene lighting.
You ned 3 lamps:

• projector Lamp: first of all, add a spotlight in a clear 3d window in Blender, and turn it more or less downwards. Set the spot as a buffered- Shadow, then in a classic-halfway toggle, then the spotbias angle more than 0.5, todo soften the border, and make it halo.
• software Lamp: add another Lamp (Hemi type) pointing behind the Camera, and parented todo it. Set its power todo a high level, more or less 2. Youll se why we use this Lamp later.
• darkening Lamp: add área Lamp(s) set todo negative power 0.5 or less, positioned upon the details todo hide from view. This kind of Lamp Will darken unnecessary parts of the scene, hiding them from view.

To make the Ground, add a plane in the top view and scale it until its borders are out the Camera field of view. Set the world colors todo black. You should se something like this (figure1). (saustics001.blend).

Now it time todo prepare our animated Caustics sequence of images or movie that well use as a texture for the projection Lamp in Blender. So, first launch Caustics Generator and set the parameters like those in figure 2 (for now these settings would not be changed. Later on you Will be able todo rapidly test diferent other settings but if you chek the automatic preview, be careful before this todo disable antialiasing by setting supersamples todo 10 and Motion Blur todo 1, otherwise drawings would be drawn very slowly). Then, After setting the directory where you estore the sequence of.bmp images, chek save output and click render animation.



Here we are: a complete tileable cyclic animation of Caustics, now fully useable in Blender on the projector Lamp. But we should use it with care, todo avoid some artefactos, because tiled textures can easily appear as artificial todo our eyes. Let return todo Blender.


Our scene opened, let select the projector Lamp and add a texture todo it. Next go todo the textures panel and set it like in figure 3. This indicates that the sequence used contains 32 frames (the parameter determined in causticsgenerator), each of them used one by one and repeated cyclically in time forever. But at this point no control of the size of the pattern used is posible. We have todo fix it.


A smart method is todo put a plane under the Ground and name it ref, for instance. The only thing todo do is todo enter Lamp buttons >>textures and input, chek the object box, and enter the same name in this field: ref. Now, the mapping of that textured Lamp Will adapt todo the size and position of the object named ref, like in figure4 (caustics002.blend).



You should now be able todo test rendering. After this, press f12.

If the patterns of the Caustics are todo large, you only ned todo resize the plane object you named referencia in lower dimensions, and if they are todo small make your referencia object bigger. It that simple. Now, with the referencia plane selected, Insert a Loc key. Then go, say, 100 frames later and slightly move (horizontally only) the referencia plane a Little. Insert a second Loc key on it. You have simulated the effect of the Wind on the Waves, making the Caustics drift along with it.



Let push the Anim button and start testing. God blending, and dont sin que todo much in it.
Lamp settings.





By dan tabonet. www.blenderart.org.