Follow us on Facebook Follow us on Twitter Linked In Flickr Watch us on YouTube My Space Blogger
التسجيل
النتائج 1 إلى 5 من 5

VRay material sub-surface effects

هذا الموضوع : VRay material sub-surface effects داخل الدورات والدروس التعليمية | 3dsMax Tutorials & Tipsالتابع الي قسم Autodesk 3D Studio Max : السلام عليكم ورحمة الله وبركاته لقد وجدت هذا الدرس الرائع عندما كنت اتصفح الانترنت انه عن الفيراي تفضلوا الدرس VRay ...

  1. #1
    مصمم مشارك

    الحالة
    غير متصل
    تاريخ التسجيل
    Jul 2006
    الدولة
    بنغازي
    العمر
    28
    المشاركات
    271
    Thanks
    0
    Thanked 0 Times in 0 Posts
    معدل تقييم المستوى
    19

    VRay material sub-surface effects

    السلام عليكم ورحمة الله وبركاته

    لقد وجدت هذا الدرس الرائع عندما كنت اتصفح الانترنت
    انه عن الفيراي
    تفضلوا الدرس
    VRay material sub-surface effects

    Many people speak today of things like absorption, translucency, sub-surface scattering. The topic of this tutorial is to give you an idea what are these effects and how to simulate them with VRay.
    We will deal exclusively with the VRay material although a large part of these effects can be achieved with the VRay map as well.
    This is the scene that we will work with for the most part of the tutorial (click the image for a larger view). Note that the teapot is not the standard MAX teapot. The standard teapot has holes, which is not a desirable property. This teapot is a completely closed mesh.
    Click here to download the scene.
    All of the above effects are sub-surface effects - they deal with light passing through the surface of objects into their interior.
    Refraction

    The most simple sub-surface light effect is refraction. In VRay all other effects are modifications of this simple one. To make our teapot refractive, set the Refraction color of the material to something other than black - for example to medium gray. The result should look something like this:

    If we set the index of refraction (IOR) to 1.0 we will get a special case of refraction - transparency, which looks like this:
    A very important fact to notice about the above picture is that the shadow of the small sphere is not visible, although it falls on the teapot. This is because the teapot's material is by default set to Double-sided. However, and this is important, for a large number of sub-surface effects we are actually interested in what happens on the outer side of surfaces, even if we are looking at them from the back. So, turn off Double-sided in the material. This time we get the following:

    A modification of the simple refraction is glossy refraction (also called frosted or blurry refraction). It is caused by the refracted rays being scattered by an object's surface. In VRay's material the amount of scattering is controlled by the refraction Glossiness parameter. When it is set to 1.0, the surface produces perfect refraction. A value of 0.0 produces perfect scattering in all directions inside the object. For example setting refraction glossiness to 0.6 gives the result below. Notice how everything seen through the teapot looks blurred. (Note that glossy refractions will try to produce caustics when used with GI. If this is undesirable, simply turn on caustics in the VRay render parameters, without enabling casutics for any individual light).

    Absorption (fog)

    Absorption occurs when the inside of an object is not fully transparent, but absorbs light as it passes through. The effect is that the object looks foggy, and thin parts are more transparent than thick parts. In VRay this effect is controlled by the Fog and Fog multiplier parameters. Let us for a moment make the Refraction color completely white and set the glossiness back to 1.0 (so that the teapot is fully and ideally transparent). Set the fog color to light blue (RGB 200, 226, 247). You can control the strength of the fog effect with the Fog multiplier. Note that the fog color and multiplier depend on the size of your object. Smaller objects will look more transparent, while bigger objects will look more opaque.
    Fog transparency = 1.0Fog transparency = 0.1
    Ideally, the fog should also affect the color of the shadow cast by the teapot. In this particular case, you can make it do so by switching on Translucency:

    Using only the effects mentioned so far, you can get quite interesting results. Here are some combinations of glossy refraction, fog and different IORs.
    Sub-surface scattering

    Sub-surface scattering (SSS, 3S) occurs when light is not only absorbed by a medium, but is also scattered (bounced) inside. Currently VRay simulates only a single bounce inside the medium. We will examine the effects of sub-surface scattering on the scene shown below. There is one omni light with VRay shadows placed above the cube (note that we could also use shadow maps). Click here to download the start scene.

    Here are the steps that will turn the cube's material into a light-scattering one.
    First, uncheck Double-sided. Next we must enable refractions, so set the refraction color to RGB (85, 85, 85). The result so far looks like this:

    Next, make the refractions glossy - for example glossiness 0.4:

    Next, turn on Translucency:

    It's not very impressive (yet), but there are two things to notice - the cube appears a little brighter, and also the shadow of the cube is transparent (because the fog color is by default set to pure white). Next set the fog color to RGB (105, 150, 115) and fog multiplier to 0.3. At this point we get the following result:

    Notice how the shadows are darker (if the transparent shadows are bothering you, you can use shadow maps). We are almost done now. The sub-surface scattering effect is there, but is too subtle to be noticed (as it usually is in nature). To make the effect stronger, increase the Light multiplier parameter of the material (not the multiplier of the omni light!) to 15.0:

    Notice how the top of the cube and its edges are brighter, because the light goes a little way into the surface. The edges are brighter, because I used GI (with irradiance map), as I did on all previous images. Here is what the picture looks like without GI:

    You can control how deep into the object light reaches by adjusting the Thickness parameter. Here is what we get if we set it to 20.0:

    Notice how the object looks softer and the light goes deeper inside. Our final image, with GI on, looks like below. Click here to download the final scene.

    Below is a set of pictures showing the effect of Refraction glossiness on the translucency effect; GI is turned off and the fog and light multipliers are a bit changed so that the difference is more noticeable (Light multiplier is 30.0 and Fog multiplier is 0.1). Notice how the image is less noisy as the glossiness goes up.
    Glossiness 0.0Glossiness 0.2Glossiness 0.4Glossiness 0.6Glossiness 0.8Glossiness 0.999
    Another set of pictures below, showing the effect of the Thickness parameter (Light multiplier is again 30.0, Fog multiplier is again 0.1, Refract glossiness is 0.8). Look closer at the shadow cast by the small sphere. Increasing the Thickness further than 60.0 will not produce any change, since it will become greater than the size of the cube.
    Thickness 0.1Thickness 2.0Thickness 10.0Thickness 20.0Thickness 30.0Thickness 60.0
    The set of pictures below show the effect of the index of refraction (IOR) on the translucency effect (Thickness is set to 20.0, the other parameters are as above). This would be best demonstrated in an animation where the cube is looked at from different directions.
    IOR 1.0IOR 1.2IOR 1.6IOR 2.0IOR 3.0IOR 5.0
    Advanced sub-surface scattering parameters

    So far we have not touched the two remaining parameters for the sub-surface scattering effect: the scattering coefficient and the forward/backward coefficient. To demonstrate their action, we will use the following scene (click here to download it).
    View from the lit (front) sideView from the shadowed (back) side
    If you open the Material Editor, you will see a material named Translucent. Apply it to the box. If you render the two camera views you will get this. Notice that when we look at the shadowed side, we can see the blurred shadow of the cylinder, falling on the other side of the box.
    Lit sideShadowed side
    Now set the Forward/backward parameter to 0.0. You should get the result below. Notice how the lit side is darker and the shadows side got brighter. This is because the material now scatters light in the direction that it travels (forward scattering).
    Lit sideShadowed side
    Set the Forward/backward parameter to 1.0 and render again. This time things are the other way round - the lit side got even brighter, and the shadowed side got darker - light is scattered back into the direction that it came from (backward scattering).
    Lit sideShadowed side
    Leave the forward/backward coefficient to 1.0. We will now play with the scattering coefficient. It's default value is 0.0 and this is what we get:

    If you set this to 1.0, you will get the following result. Notice that the scattering is completely gone, and we get a very smooth (and very uninteresting) result.

    More examples

    Here are several more experiments with various settings:
    The cube is lit by a single spot light with small falloff.
    An attempt at polished marble.
    An experiment with one of Max 3.1 standard example scenes - with an without sub-surface scattering.

    The same but the diffuse map is tinted green.

    دروس الخامات من الصفر الى الاحتراف

  2. #2
    مصمم مشارك

    الحالة
    غير متصل
    تاريخ التسجيل
    Sep 2006
    الدولة
    UAE
    المشاركات
    376
    Thanks
    0
    Thanked 0 Times in 0 Posts
    معدل تقييم المستوى
    20
    مشكور أخي على الدرس ولكن ولا صورة تظهر عندي أرجو محاولة وضع الصور مرة أخرى أو أن تعطينا أسم الموقع ،وبارك الله فيك.
    ان الله ولي التوفيق ،والله على كل شيء قدير

  3. #3
    مصمم مشارك

    الحالة
    غير متصل
    تاريخ التسجيل
    Jul 2006
    الدولة
    بنغازي
    العمر
    28
    المشاركات
    271
    Thanks
    0
    Thanked 0 Times in 0 Posts
    معدل تقييم المستوى
    19
    تفضل يا اخي الموقع يوجد به الكثير من الدروس الرائعة للفيراي
    http://www.vrayelite.com/mytutorials.php

  4. #4
    مصمم مشارك

    الحالة
    غير متصل
    تاريخ التسجيل
    Sep 2006
    الدولة
    UAE
    المشاركات
    376
    Thanks
    0
    Thanked 0 Times in 0 Posts
    معدل تقييم المستوى
    20
    مشكور على الموقع.

  5. #5
    مصمم مشارك

    الحالة
    غير متصل
    تاريخ التسجيل
    Jul 2006
    الدولة
    بنغازي
    العمر
    28
    المشاركات
    271
    Thanks
    0
    Thanked 0 Times in 0 Posts
    معدل تقييم المستوى
    19
    عفواً وانشاء الله سوف ابحث على مواقع اخري


 

 

المواضيع المتشابهه

  1. [Material]: 3D Max VRAY material
    بواسطة cgway center في المنتدى دروس تعليمية اجنبية | Youtube , Vimeo
    مشاركات: 1
    آخر مشاركة: 19 / 07 / 2013, 24 : 10 AM
  2. مشكلة في vray material slots
    بواسطة ashraf_tech في المنتدى Autodesk 3D Studio Max
    مشاركات: 13
    آخر مشاركة: 24 / 01 / 2013, 19 : 02 PM
  3. [Material]: Tweaking VRay Material Texture
    بواسطة مسلمة في المنتدى الدورات والدروس التعليمية | 3dsMax Tutorials & Tips
    مشاركات: 2
    آخر مشاركة: 13 / 10 / 2011, 16 : 11 PM
  4. Vray material convert ????
    بواسطة loveybambino في المنتدى Autodesk 3D Studio Max
    مشاركات: 1
    آخر مشاركة: 13 / 09 / 2008, 28 : 09 PM

الكلمات الدلالية لهذا الموضوع

المفضلات

ضوابط المشاركة

  • لا تستطيع إضافة مواضيع جديدة
  • لا تستطيع الرد على المواضيع
  • لا تستطيع إرفاق ملفات
  • لا تستطيع تعديل مشاركاتك
  •  
الساعة الآن 31 : 11 PM
Powered by vBulletin® Version 4.2.3
Copyright © 2017 vBulletin Solutions, Inc. All rights reserved.
Search Engine Optimization by vBSEO