create caustic effect

In this tutorial we will start up with this build up scene which i have created using Nurbs Revolve Tool and Plannar Tool in Maya.
	In this scene we are having one outer boundary which will act as the wall, then we have a Bowl and from that bowl Ii have created a liqiod Material. Now lets start the proceedings.
	Get the hypershade Window and create 2 Blinn Materials, name the one with Bowl Material and the another with Liquid Material.
	Double Click the Bowl Material to get into its Attribute Editor and do the settings as in the image below:
	Scroll down to Specular Shading of the same material and don the changes as in the image
	Further scroll down to the raytrace options and turn on the refractiona dn set the refraction index to 1.3 as it is the default refraction index limit for the glass.

Thats what we done with the Bowl Material, now select the Liquid Material and get into its attribute Editor byy pressing Ctrl+A. in the liquid Material change the color to any color you want to be the color of your liquid as I changes it to green and crank up the transparencey as in the image below.
	scroll down to the Specular shading and change the eccentricity to 0.06 as the changes we did for the bowl material, get the specular roll off to 1 and crank to specular color to something as in the image.
	Turn the refraction on and set the refraction index to 1.32 a little different to that we have for the bowl material.
	Now we are done with the 2 Blinn materials , we have to do with some more settings in these material, that we will do in the later part of the tutorial.
	Now do one thing assign bothe the materials one by one to its respective objects. Like bowl material to bowl and liquid material to the liquid object that you created in the scene.
	Now you can see that as our materials are transparent , you casn do one thing turn on the wireframe shaded to make the bowl obejct appear or can say visible.
	Now, its a time to make some lighting in the scene, and the way we do that by creating one directional light and one area light ion our scene and plan it somewhere in the scene as you can seee in the image below
	As you can see in the image in the previous page we have scale up both of the lights. In fact scaling up the directional light does'nt effect the intensity in our scene , but in the case for area light scaling up does effect the intensity in our scene.   Select your directional light and press Ctrl+A to get into its Attrribute Editor Window and do the changes as in the image below.     Increase the intensity to 1.5, if needed to be modified we will do that later.     Now select Area light and get into Attribute Editor Window and do the changes as in the image below. crank down the intensity to 0 as we want to emit photos from this light          Sroll down to mental ray in the same window to make photons emits from this light, get into the caustics and global illumination section of the mental ray, turn on the emit photons and keep the settings to default.           Now its time to render out our scene and have a look at how much we have proceed.     This is the render whic we have come up with. This scene is render with maya software renderer. As in our scene we want to emit photons from our area light for that we have to get into the mental ray renderer and the way we do that by switching to the mental ray from maya software in render view window as in the image below       And now if we a take a render out we see a whole different render image in front of us. Now in the same render view window click on the render settings icon as highlighten in the image below     As we click on the render settings icon its window will be open and now its time to make some changes in this window. As you can see in this window there is one custom tab and one mental ray tab, click on the mental ray tab.     In mental ray tab look for the Raytracing Options, as you click on the raytracing its settings will open. In the reflection increase the limit to 7 and same in the refraction and increase the max. trace depth to 10.       And now render out the scene and we come up with whole new render image. The one which I have come up with is below in the image.       Note: Explanation for Raytracing Options   As in the image below you can see light have to pass through from the 6 surfaces and in order to make that happen we have increased up that reflection limit to 7 and the same we did for the refraction limit.     Surface 3 and surface 4 are liquid object surface and the other surfaces are for the bowl.   Once again open the render settings and in the mental ray tab, turn on the caustics and now render the scene.       select your area light and in the emit photons options play around with settings of intensity, exponent and caustic photosn as these are very much dependable with the particular scene. you can see my settings in the image below to get to the desired result. you should try your own settings as these are very much scene dependable.         Open up your Hypershade and select the bowl material and press Ctrl+A to get into the Attribute Editor, as the attribute window opens scroll down to the mental ray tab and in that scroll down further more for the Photon Attributes sub-tab.      Turn off the dreive from Maya and click on the Take Settings From Maya.     Take the Diffuse to something like 0.2 and also make some changes in the color.   Now select the liquid material and same as we did for the bowl material, turn off derive from Maya and Click on Take Settings from Maya. Turn off absorb box and decrease the Diffuse to 0 and color value also and also change the transparency color and its value.       Now render out the scene and see the difference.   Open up the render settings again and in that look for Caustics and Global Illumination, click on that after you click that you see caustic options and in that set the caustic filter type to Cone       Select the directional light and turn off the emit specular option and now render the scene, you see a nice amount of difference.

Posted in Maya 3D