DETAILS IN MATERIAL

Quickly flash back to the recent tutorial, step 1, create the whole ambience of the area by placing omni lights (ambient only) in the middle of the room as the main ambient color, make the far attenuation range fitted to the room and placing skylight ambience (light blue omni with ambient only) on the roof top. This means to create the effect of the skylight scattered around the roof and walls. See picture the scene ,lit up with the "AMBIENT ONLY" omni. The ambient pass is successfully done.


step 1, create the whole ambience

Tips : Actually in this step, we might not put in all the real material into the scene first as some materials have reflection or whatever that make the rendering time longer . I assign a white color material to all the objects first. This is to make the entire scene easier to control lighting as we can see the brightest and darkest part of all the object clearer and more accurate with white color.

step 2, diffuse and specular pass

created by adding 1. free direct (diffuse and specular) as to cast indirect illumination shadows (soft shadow) 2. skylight, placing blue omni (diffuse and specular) use cast shadow. May we replace white color with the real materials in this stage as to correct all detail of specular and diffuse color and level roughly.



step 3, brightest part to be added in this stage

Sunlight and indirect illumination of sunlight from floor and wall.. See how and where I place these light in the scene.


We might have finished the entire perspective here from the last tutorial.

Sometimes, we find that some material ,kept in our library before doesn't have good effect when we reuse it again in a current scene. It doesn't go well or match with the current lighting ie. no spcular or reflection is too bright. Making the reallistic material in a big scene or a scene that is lit up with so many light is not as easy as a still light image that require less number of light. Suggest that we should go into the material's details after we've finished lighting up the scene. The concept is to fake the material physical condition follow the lighting as to make it more realistic. In this tuotorial I will mentionded to a few examples for you to have idea that can be applied to your own way.

step 4, Coustic

I found that the sunlight illumination from floor to the environment is not enough reallistic. I placed 2 omni at the small wavy water and apply projector map into it, using cellular maps. The cellular map on projector give the effect nearest to real coustic. Anyway, I still can not fake the coustic as realistic as some GI plugin but at least pust some more fuzziness into the images.


step 5. Go in to the material's detail.

Oneday I walked in to a huge lobby of a building with all granite floor. I notice that on the granite floor have an ood reflection eventhough it looked like smooth plain floor. The reflection looks distorted and scattered into piece by piece and doesn't join together. I went back home and tried to fake such effect but no such option in raytrace (or have and I don't know). So there is another way to do that is to draw a granite piece by piece join together but I find it wasting the time so much very much and the edge of each granite may not join correctly with our eye estimation.

2.1 Distortation effect.

In this scene, I drew a plain as another layer of the foreground floor with 8x8 segment, assign marble material on it and UVW map. Add noice modifier onto it. This is to give every pieces of marble not too flat. So when render, we will see the distorted reflection on the marble continually in every piece of marble because the whole polygon on plain is in the same smoothgroup. The distortation's appeared on the marble because of the noise modifier. I added editmesh modifier to give each polygon different in smoothing group numbers. Extrude some rectangle polygons randomly but give the amount as less as possible. Rendered again. The distoration of the reflection seems independent just like in picture... and that's the effect I want.

Distorted reflection appears continually on the marble floor as the whole polygons is in the same smoothing group number.

2.2 Faking phisical condition of materials to match the lighting in the scene.

At the begining of this drawing, I used the material from my library but when I made the final rendering, the effect of specualr level appeared acceptable but didn't have enough details to make the scene more realistic. Actually the specualr level of the original material is adjusted correctly. I faked the rendering again by increase the specualr level as to make the scratch (I use scratch map for specular level map) appear more obvious and that's another idea to make the scene more reallistic. Not only the specular, the diffuse level or bump map parameter may be changed to be more obvious in other scene and I hope you can understand this concept more or less hope you can apply to your own way. Remember that material follow light whenever there are more light in the scene but light can follow material when there is lesser light numbers in the scene.



source: http://www.3dm3.com/

CAR PAINT AND MODERN MATERIAL

The two specular highlights will give an optimal light reflection to your object in order to show in a very soft and for the human eye pleasureful way the shapes of you objects.

To create two specular highlights you must change the BLINN shader to MULTY-LAYER. This allows you to have 2 independent specular highlights (in Multy-Layer they are called First Specular Layer and Second Specular Layer). One must be very soft the other very hard/strong.



Go to the first specular highlight slot (it is called specular layer)and adjust it until you have a large shape (glossiness) which is not too bright (level). Then do the opposite with the second specular layer: small shape and very bright. After this step go to Maps and add to the reflection map Raytrace. Set the reflection amount to more or less 20

To have more control of the specular highlights in the rendering you can use in your scene a SPECIAL "MR.Area Omni" light (normaly it is better to use MR.Area Omni if you use Mental Ray to make your rendering, but in this case you can use also a normal Omni light). After you have placed the light in the correct location make a right mouse button click on the MR Area Omni and disable "AFFECT DIFFUSE"

After this step this MR.Area Omni will create only specular highlights on the materials. We will use that MR.Area Omni only to create this specular effects that normally is visible on metalized car paint. In this way we have much more control of the position, color and brightness of the specular highlights. Disable the shadows in the MR.Area Omni.

This technique is very helpful if you need a higher number of specular highlights than the existing light sources (that you must create for normal illumination) are already creating on the car paint material.

It is also possible to create a specular color which is different than white. With changing the specular color you can simulate the classical car paints that you can see in the car-tuning environment where often we have a mix of two different colors (diffuse color + specular color). This makes the material more interesting. Here below you have a sample of a mix of more colors. In this case we have a red diffuse color, a blue first specular layer color and a white second specular layer color.



Here below we have exactly the same scene, but without the EXTRA omni lights. The difference is strongly visible. In this sample you can understand how important it can be to use the technique described in this tutorial

Tip 1:

If you go to use many Mr Omnies for an object because you want to create many different specular highlights, you will risk to create a less visible shadow of an object. In this case it is necessary to use Ambient/Occlusion to avoid this problem.

Tip 2:

If you have other objects in the scene that have normal materials and have NOT to be affected by the Omnies, remember to exclude them from the Omnies with the exclude button from the modify panel.

source: http://www.tutorialized.com/

CAUSTIC WITH MENTALRAY PLUGINS

Caustics are really great light effects that you can observe in liquids, glass objects and gems. We are able to simulate this effect with 3D Studio Max perfectly. This tutorial about Caustics will work only if you enable "Mental Ray”!

Step 1: Let's Create a small room like on image "1" (try to do that in realistic sizes, it is important that you make the setup of the "unit system", only in this way Mental Ray will give you an optimal end result since it will consider all measurements of the objects in the scene for the final rendering).Now create your lights to illuminate the room.

There are several techniques to create a correct illumination. In the case of the room I have created 3 long "free area lights" like on below image (you can find them under photometric lights).



Step 2: Place them under tree long boxes. Select the bottom polygons of the boxes and assign them a white self illuminated material like below image.



Step 3: To get a more realistic illumination I have enabled Final Gather in "indirect illumination". I put a quite high number in "samples" to make the final rendering (600).



Step 4: After you made the room you must create the water. We can do that with a simple box. To create the small waves on the surface you have different possibilities (or with a material or by polygons). For transparent water material creates a "Raytrace" material (it must be transparent and a bit reflective). To create a wave effect put in the "bump map" a "noise"-map with a quite small size; to simulate trough geometry deformation the noise/wave effect you must apply to the box a "noise modifier". The wave size will influence the caustic shapes. Big waves/noise = Big caustic shapes!

After you made all the objects you must create a "MR Area Omni" light on the top of the water in the center of the room like step 2 image. Now make a right mouse button click on the MR. Area Omni and disable "AFFECT SPECULAR" and "AFFECT DIFFUSE". Get a more realistic illumination I have enabled Final Gather in "indirect illumination". I put a quite high number in "samples" to make the final rendering (600).



Step 5: After this step this MR.Area Omni will NOT anymore affect the illumination of the room. We will use that MR.Area Omni ONLY to create the caustic effects. In this way we have much more control of the caustic position, color and brightness. Disable shadows in the MR.Area Omni.

Now select the MR.Area Omni and all other objects except the lights that you have created for illumination (Free area lights). Make a right mouse button click on all the selection and select properties.





Final Step: Go on the "Mental Ray" panel and check "GENERATE CAUSTICS”. This is necessary in order to have a caustic effect on the objects. Now we must go to the "INDIRECT ILLUMINATION" panel and enable "CAUSTICS".

To improve the quality of the caustics (better/clearer shapes) you must go to "LIGHT Properties" and put a VERY high number in "AVERAGE CAUSTIC PHOTONS PER LIGHT".I put a bit less than one million. For test renderings it is enough to put 10.000. The higher the number, the better will be the effect. Of course it will take much more time to render the entire scene. You can put very high numbers in multiplier (MR.Area Omni) to create a very bright caustic effect. If you change the light color of the MR.Area Omni you will change the color of the caustics ( blue omni color = blue caustics). To have a blue color of the illumination under water the water material should have a blue color in diffuse and transparency. Hope you liked this tutorial.



source : http://www.tutorialized.com/