تويت
السلام عليكم و رحمة الله ..
انطلاقا من رغبتي بتفعيل منبر المايا .. ووضع الدروس و مشاهدة التطبيقات .. و الفائدة الكبيرة للجميع و التي لا تتأتى إلا بالتطبيق و الممارسة ..
أضع بين أيديكم هذا الدرس .. الذي أجده مفيدا جدا في استخدام المنتال راي في الإضاءة و الإخراج الداخلي
راجيا ً من الإخوة المختصين بالمايا عندنا في المحور ..
paciman hakem ramadan yasser >> و جميع الإخوة المحترفين و أصحاب الخبرة
متابعة التطبيقات و تقييمها و نقدها .. حتى يتم التعديل و نصل إلى أفضل مستوى ..
طبعا ً الدرس باللغة الإنجليزية
و اتمنى من جميع الأعضاء المعنيين بالفائدة التطبيق .. و إرفاق تطبيقاتهم للدرس حتى نستفيد
في نهاية الدرس .. سوف يخرج كل منا بنتيجة مثل هذه :
----------------------------------------------------------------------------------------------------
This tutorial comes from the experience gained by me and other treddi.com members during the last months of tests made for reaching good quality interior renderings with Mental Ray. So I want to begin thanking all those who have contributed to the tests and shared his/her own experiences and settings. Particularly, I wish to thank Stefano (gtsix) for the English translation and Alessando (Pantich78), that has been the first one to read the draft of this tutorial and provided interesting cues that allowed me to deepen some aspects of the topic. The tutorial can easily be followed by whoever uses mental ray (on maya/3d max/xsi/hudini and others) What I will illustrate is just one of the many possible methods for achieving this kind of illumination, and should be considered as a starting point to begin your own experimentations with mental ray, from many people around the world considered one of the most difficult rendering engine to use for this type of task. Some of the steps you’ll find on this tutorial will seem to be repetitive or unmeaningful, but I decided to keep all of them in order to give the reader all the info he/she needs in the clearest way possible. After reading and understanding this tutorial, he/she’ll be able to optimize his/her own personal method, skipping some steps or mixing others. It’s just a matter of experience! ;-) This is a wide subject, so I have chosen to describe the method in a very general way and to try to touch a bit of all of the correlated topics. If anyone should need some help, just write me (obviously it could be possible that I won’t have a ready-to-use answer, but I will try to help you anyway
). In this tutorial I will assume that the reader has a basic knowledge of Maya and Mental Ray. These are the tutorials sections: 1. Basic lighting system 1.1 Light choosing and positioning 1.2 Lights settings 1.2.1 Sunlight 1.2.2 “Diffuse” light 1.3 How to “balance” the lights in the scene 1.4 Final Gather 1.4.1 How to set up the Final Gather 1.5 How to set up the final rendering 2. Other types of lighting systems 1. Basic lighting system Before writing this tutorial I have done many tests using various types of lights and settings. You’ll find them here The lights that I’m going to use in this tutorial are those that I think are more effective in this kind of rendering, in terms of quality/speed and in terms of matching an ideal photorealistic lighting system. I’ll use of two types of lights, the first one simulates the direct light and the other one will simulate the “diffuse” light. 1.1 Light choosing and positioning First of all you have to download the tutorial scene. It’s available in these formats: .obj .mb .3ds Open the file. It’s japan-style room (already famous over the www.treddi.com forum ). Set the scene units to centimeters. Remember that after importing a 3ds or .obj model into Maya you will have the settings “Visible in reflection” e “Visible in refraction” disabled, so you will have to turn them on manually under the “Render Stats” Now we can put the lights in our scene. a. Sunlight With the first light you will simule the sunlight. Considering the several possibilites I decided to use a spotlight, later on we will see the alternatives. Position one spot far enough from the room, so you can use a little opening angle (20° approximately) remember that the spot does not have parallel beams, so using a little angle will allow you to simulate better the ideal sunlight. b. “Diffuse” light Create a point light and open the light’s attributes. Under the mental ray section turn on the “Area Light” option. Move the light until it’s lined up with the window and scale its radius so that the edges approaches the opening-width of the window (you can eventually reduce it a bit to prevents problems with overexposed areas on the walls near the window) In the following images you can see how I positioned the lights.
[/RIGHT]
- Link alla versione italiana:
http://www.treddi.com/forum/index.php?showtopic=4858
Immagine ridotta: 80% della dimensione originale [ 800 x 580 ]
English Translation by Gtsix http://www.pixeloverdrive.com
This tutorial comes from the experience gained by me and other treddi.com members during the last months of tests made for reaching good quality interior renderings with Mental Ray.
So I want to begin thanking all those who have contributed to the tests and shared his/her own experiences and settings.
Particularly, I wish to thank Stefano (gtsix) for the English translation and Alessando (Pantich78), that has been the first one to read the draft of this tutorial and provided interesting cues that allowed me to deepen some aspects of the topic.
The tutorial can easily be followed by whoever uses mental ray (on maya/3d max/xsi/hudini and others)
What I will illustrate is just one of the many possible methods for achieving this kind of illumination, and should be considered as a starting point to begin your own experimentations with mental ray, from many people around the world considered one of the most difficult rendering engine to use for this type of task.
Some of the steps you’ll find on this tutorial will seem to be repetitive or unmeaningful, but I decided to keep all of them in order to give the reader all the info he/she needs in the clearest way possible. After reading and understanding this tutorial, he/she’ll be able to optimize his/her own personal method, skipping some steps or mixing others. It’s just a matter of experience! ;-)
This is a wide subject, so I have chosen to describe the method in a very general way and to try to touch a bit of all of the correlated topics.
If anyone should need some help, just write me (obviously it could be possible that I won’t have a ready-to-use answer, but I will try to help you anyway ).
In this tutorial I will assume that the reader has a basic knowledge of Maya and Mental Ray.
These are the tutorials sections:
1. Basic lighting system
1.1 Light choosing and positioning
1.2 Lights settings
1.2.1 Sunlight
1.2.2 “Diffuse” light
1.3 How to “balance” the lights in the scene
1.4 Final Gather
1.4.1 How to set up the Final Gather
1.5 How to set up the final rendering
2. Other types of lighting systems
1. Basic lighting system
Before writing this tutorial I have done many tests using various types of lights and settings. You’ll find them here
The lights that I’m going to use in this tutorial are those that I think are more effective in this kind of rendering, in terms of quality/speed and in terms of matching an ideal photorealistic lighting system.
I’ll use of two types of lights, the first one simulates the direct light and the other one will simulate the “diffuse” light.
1.1 Light choosing and positioning
First of all you have to download the tutorial scene. It’s available in these formats:
.obj
.mb
.3ds
Open the file. It’s japan-style room (already famous over the www.treddi.com forum ). Set the scene units to centimeters. Remember that after importing a 3ds or .obj model into Maya you will have the settings “Visible in reflection” e “Visible in refraction” disabled, so you will have to turn them on manually under the “Render Stats”
Now we can put the lights in our scene.
a. Sunlight
With the first light you will simule the sunlight. Considering the several possibilites I decided to use a spotlight, later on we will see the alternatives.
Position one spot far enough from the room, so you can use a little opening angle (20° approximately) remember that the spot does not have parallel beams, so using a little angle will allow you to simulate better the ideal sunlight.
b. “Diffuse” light
Create a point light and open the light’s attributes. Under the mental ray section turn on the “Area Light” option. Move the light until it’s lined up with the window and scale its radius so that the edges approaches the opening-width of the window (you can eventually reduce it a bit to prevents problems with overexposed areas on the walls near the window)
In the following images you can see how I positioned the lights.
1.2 Lights settings
In order to understand the behavior of the lights, I suggest you to begin the tests with only one light turned on.
Assign a white shader (I suggest a Lambert or DGS without glossy and specular) to your model.
1.2.1 Sunlight
Select the point light and disable it (deselect the following options: “Illuminates by Default”, “Emit Diffuse”, “Emit Specular")
Select the spot light and edit its attributes: turn on the raytraced shadows with the default options (you can give a slight angle variation to the beams if you want)
Open the “Renderglobal” > “Quality Presets” menu and select “Preview”
to get a quick render of your first test.
If you followed the instructions correctly you should get something like this:
Change the light intensity until the illumination level of the visible areas seems good to you.
-Now activate the GI in the “Renderglobal” menu and set the “Global Illum Accuracy” to 512, keeping the “Global Illum Radius” to 0 (default).
-Change the settings of the i]“Raytracing”[/i] (4-4-8 should go well)
-Also turn on “Emit Photons” in the attributes of the spotlight and perform a test render to examine the illumination levels of the parts of the room which are not directly lit by the spotlight.
Remember that the amount of the light that will effect your model is also directly related to the distance from the object.
The further from the model your light is, the higher you will have to set the intensity of the photons. For example I reached 185.000.000 to get this result:
Now increase the number of the photons to 500.000 and your render will look something like this:
I suggest you to activate the “Progressive Messages” (“Renderglobal” > “Translation” > ”Progressive messages”) , so you can monitor the rendering times of the different tests.
1.2.2 “Diffuse” light
Now we will perform the same steps for our point light (that we have previously transformed in a Mental Ray Area Light, see chapter
- Disable the Spotlight (remember you have to check-off “Emit Photons”)
- Activate the raytrace shadows of the point light; I suggest you to use a “Decay linear”
- As for your Photon settings, use the same photon settings you used in your spotlight except for the intensity, which should be very small (in this case I’m using 100.000) .
- Perform the same render as done for the spotlight.
Only direct light:
(Don’t worry about the graininess of the shadows, we will tweak it later adjusting the settings for the final render)
direct light + photons
1.3 How to “balance” the lights in the scene
Activate both the lights and perform another render.
If you are lucky you’ll get the correct lighting and illumination, but more likely you’ll have to tweak your light settings to get the result you have in mind.
Obviously the changes your’re going to do will vary depending on the lighting effect you want to reach for your render!
Here's my test:
Don’t worry if some of the areas are overexposed, when we’ll activate the final gather the problem will be almost fixed.
Anyway, if you want you can do a small test: do a region render of the most significant areas of your scene, simply activating the final gather with the following settings: “rays”: 100 “min max radius”: 0/0 and “rebuild photon map” turned off. This is my result:
If you still have problems with over-exposed ares or getting weird artifacts I suggest you to slightly decrease the photons intensity of the spotlight and also slightly decrease the intensity of the point light (mostly if the over-exposed areas are those directly affected by the area light).
Now that the light seems more balanced we’ll start optimizing the GI.
This is the Maya “Caustic and Global illumination” panel.
Here you are some short descriptions of the main GI settings:
- “Global Illum Accuracy”: this value, that we have already set to 512, represents the quality of the photon map.
- “Global Illum Radius”: we’ll set it later. As for now just remember that the default value is 0: with this value mental ray calculates the best setting for the render (in 90% of cases you can keep this setting). Anyway, to optimize our rendering times we’ll hand-calculate it.
- “Max Photon Depth”, “Max Reflection Photons” e “Max Refraction Photons”, are the settings of the well-known photon bounces. They set the number of bounces that our photons will perform before they stop.
The first value indicates the maximum amount of bounces.
Now we have to choose the Photon Volume Radius and the Max Photon Depth. Talking about Depth, I’m getting good results using the default settings (5-5-5).
Remember that higher depth values means more light in the dark areas of your render, but it will also increase your render times.
As I said before, changing the Photon Volume Radius will allow us to optimize our render speed.
You can test it performing a render (GI only) with the Photon Volume Radius set to 0 (best quality).
Have a look at the render times: 50 seconds (on my workstation off course)
Do your experiments increasing the radius value and see how your render-time changes (obviously along with the image quality)
You can start with very low radiuses (1 for example) and increase the value until you get a result similar to the first render (with radius 0), but with lower render-times. Remember that the radius is expressed in local scene units.
When performing these tests turn off “rebuild photon map”, in order to speed up the test renders.
Remember that in this phase even the smaller time gap between your tests could lead to considerably different rendering speeds when working on the final render. So, every second counts!
Here you will see my radius-changing tests:
I chose radius = 15
الجزء 2 ..
في الأسفل ..
طبعا الدرس منقول من موقع أجنبي للفائدة ..
سأرفق تطبيقي خلال فترة قريبة إن شاء الله .
انطلاقا من رغبتي بتفعيل منبر المايا .. ووضع الدروس و مشاهدة التطبيقات .. و الفائدة الكبيرة للجميع و التي لا تتأتى إلا بالتطبيق و الممارسة ..
أضع بين أيديكم هذا الدرس .. الذي أجده مفيدا جدا في استخدام المنتال راي في الإضاءة و الإخراج الداخلي
راجيا ً من الإخوة المختصين بالمايا عندنا في المحور ..
paciman hakem ramadan yasser >> و جميع الإخوة المحترفين و أصحاب الخبرة
متابعة التطبيقات و تقييمها و نقدها .. حتى يتم التعديل و نصل إلى أفضل مستوى ..
طبعا ً الدرس باللغة الإنجليزية
و اتمنى من جميع الأعضاء المعنيين بالفائدة التطبيق .. و إرفاق تطبيقاتهم للدرس حتى نستفيد
في نهاية الدرس .. سوف يخرج كل منا بنتيجة مثل هذه :
---------------------------------------------------------------------------------------------------- This tutorial comes from the experience gained by me and other treddi.com members during the last months of tests made for reaching good quality interior renderings with Mental Ray. So I want to begin thanking all those who have contributed to the tests and shared his/her own experiences and settings. Particularly, I wish to thank Stefano (gtsix) for the English translation and Alessando (Pantich78), that has been the first one to read the draft of this tutorial and provided interesting cues that allowed me to deepen some aspects of the topic. The tutorial can easily be followed by whoever uses mental ray (on maya/3d max/xsi/hudini and others) What I will illustrate is just one of the many possible methods for achieving this kind of illumination, and should be considered as a starting point to begin your own experimentations with mental ray, from many people around the world considered one of the most difficult rendering engine to use for this type of task. Some of the steps you’ll find on this tutorial will seem to be repetitive or unmeaningful, but I decided to keep all of them in order to give the reader all the info he/she needs in the clearest way possible. After reading and understanding this tutorial, he/she’ll be able to optimize his/her own personal method, skipping some steps or mixing others. It’s just a matter of experience! ;-) This is a wide subject, so I have chosen to describe the method in a very general way and to try to touch a bit of all of the correlated topics. If anyone should need some help, just write me (obviously it could be possible that I won’t have a ready-to-use answer, but I will try to help you anyway
). In this tutorial I will assume that the reader has a basic knowledge of Maya and Mental Ray. These are the tutorials sections: 1. Basic lighting system 1.1 Light choosing and positioning 1.2 Lights settings 1.2.1 Sunlight 1.2.2 “Diffuse” light 1.3 How to “balance” the lights in the scene 1.4 Final Gather 1.4.1 How to set up the Final Gather 1.5 How to set up the final rendering 2. Other types of lighting systems 1. Basic lighting system Before writing this tutorial I have done many tests using various types of lights and settings. You’ll find them here The lights that I’m going to use in this tutorial are those that I think are more effective in this kind of rendering, in terms of quality/speed and in terms of matching an ideal photorealistic lighting system. I’ll use of two types of lights, the first one simulates the direct light and the other one will simulate the “diffuse” light. 1.1 Light choosing and positioning First of all you have to download the tutorial scene. It’s available in these formats: .obj .mb .3ds Open the file. It’s japan-style room (already famous over the www.treddi.com forum ). Set the scene units to centimeters. Remember that after importing a 3ds or .obj model into Maya you will have the settings “Visible in reflection” e “Visible in refraction” disabled, so you will have to turn them on manually under the “Render Stats” Now we can put the lights in our scene. a. Sunlight With the first light you will simule the sunlight. Considering the several possibilites I decided to use a spotlight, later on we will see the alternatives. Position one spot far enough from the room, so you can use a little opening angle (20° approximately) remember that the spot does not have parallel beams, so using a little angle will allow you to simulate better the ideal sunlight. b. “Diffuse” light Create a point light and open the light’s attributes. Under the mental ray section turn on the “Area Light” option. Move the light until it’s lined up with the window and scale its radius so that the edges approaches the opening-width of the window (you can eventually reduce it a bit to prevents problems with overexposed areas on the walls near the window) In the following images you can see how I positioned the lights. [/RIGHT]
- Link alla versione italiana:
http://www.treddi.com/forum/index.php?showtopic=4858
Immagine ridotta: 80% della dimensione originale [ 800 x 580 ]English Translation by Gtsix http://www.pixeloverdrive.com
This tutorial comes from the experience gained by me and other treddi.com members during the last months of tests made for reaching good quality interior renderings with Mental Ray.
So I want to begin thanking all those who have contributed to the tests and shared his/her own experiences and settings.
Particularly, I wish to thank Stefano (gtsix) for the English translation and Alessando (Pantich78), that has been the first one to read the draft of this tutorial and provided interesting cues that allowed me to deepen some aspects of the topic.
The tutorial can easily be followed by whoever uses mental ray (on maya/3d max/xsi/hudini and others)
What I will illustrate is just one of the many possible methods for achieving this kind of illumination, and should be considered as a starting point to begin your own experimentations with mental ray, from many people around the world considered one of the most difficult rendering engine to use for this type of task.
Some of the steps you’ll find on this tutorial will seem to be repetitive or unmeaningful, but I decided to keep all of them in order to give the reader all the info he/she needs in the clearest way possible. After reading and understanding this tutorial, he/she’ll be able to optimize his/her own personal method, skipping some steps or mixing others. It’s just a matter of experience! ;-)
This is a wide subject, so I have chosen to describe the method in a very general way and to try to touch a bit of all of the correlated topics.
If anyone should need some help, just write me (obviously it could be possible that I won’t have a ready-to-use answer, but I will try to help you anyway
).In this tutorial I will assume that the reader has a basic knowledge of Maya and Mental Ray.
These are the tutorials sections:
1. Basic lighting system
1.1 Light choosing and positioning
1.2 Lights settings
1.2.1 Sunlight
1.2.2 “Diffuse” light
1.3 How to “balance” the lights in the scene
1.4 Final Gather
1.4.1 How to set up the Final Gather
1.5 How to set up the final rendering
2. Other types of lighting systems
1. Basic lighting system
Before writing this tutorial I have done many tests using various types of lights and settings. You’ll find them here
The lights that I’m going to use in this tutorial are those that I think are more effective in this kind of rendering, in terms of quality/speed and in terms of matching an ideal photorealistic lighting system.
I’ll use of two types of lights, the first one simulates the direct light and the other one will simulate the “diffuse” light.
1.1 Light choosing and positioning
First of all you have to download the tutorial scene. It’s available in these formats:
.obj
.mb
.3ds
Open the file. It’s japan-style room (already famous over the www.treddi.com forum ). Set the scene units to centimeters. Remember that after importing a 3ds or .obj model into Maya you will have the settings “Visible in reflection” e “Visible in refraction” disabled, so you will have to turn them on manually under the “Render Stats”
Now we can put the lights in our scene.
a. Sunlight
With the first light you will simule the sunlight. Considering the several possibilites I decided to use a spotlight, later on we will see the alternatives.
Position one spot far enough from the room, so you can use a little opening angle (20° approximately) remember that the spot does not have parallel beams, so using a little angle will allow you to simulate better the ideal sunlight.
b. “Diffuse” light
Create a point light and open the light’s attributes. Under the mental ray section turn on the “Area Light” option. Move the light until it’s lined up with the window and scale its radius so that the edges approaches the opening-width of the window (you can eventually reduce it a bit to prevents problems with overexposed areas on the walls near the window)
In the following images you can see how I positioned the lights.
1.2 Lights settings
In order to understand the behavior of the lights, I suggest you to begin the tests with only one light turned on.
Assign a white shader (I suggest a Lambert or DGS without glossy and specular) to your model.
1.2.1 Sunlight
Select the point light and disable it (deselect the following options: “Illuminates by Default”, “Emit Diffuse”, “Emit Specular")
Select the spot light and edit its attributes: turn on the raytraced shadows with the default options (you can give a slight angle variation to the beams if you want)
Open the “Renderglobal” > “Quality Presets” menu and select “Preview”
to get a quick render of your first test.
If you followed the instructions correctly you should get something like this:
Change the light intensity until the illumination level of the visible areas seems good to you.
-Now activate the GI in the “Renderglobal” menu and set the “Global Illum Accuracy” to 512, keeping the “Global Illum Radius” to 0 (default).
-Change the settings of the i]“Raytracing”[/i] (4-4-8 should go well)
-Also turn on “Emit Photons” in the attributes of the spotlight and perform a test render to examine the illumination levels of the parts of the room which are not directly lit by the spotlight.
Remember that the amount of the light that will effect your model is also directly related to the distance from the object.
The further from the model your light is, the higher you will have to set the intensity of the photons. For example I reached 185.000.000 to get this result:
Now increase the number of the photons to 500.000 and your render will look something like this:
I suggest you to activate the “Progressive Messages” (“Renderglobal” > “Translation” > ”Progressive messages”) , so you can monitor the rendering times of the different tests.
1.2.2 “Diffuse” light
Now we will perform the same steps for our point light (that we have previously transformed in a Mental Ray Area Light, see chapter
- Disable the Spotlight (remember you have to check-off “Emit Photons”)
- Activate the raytrace shadows of the point light; I suggest you to use a “Decay linear”
- As for your Photon settings, use the same photon settings you used in your spotlight except for the intensity, which should be very small (in this case I’m using 100.000) .
- Perform the same render as done for the spotlight.
Only direct light:
(Don’t worry about the graininess of the shadows, we will tweak it later adjusting the settings for the final render)
direct light + photons
1.3 How to “balance” the lights in the scene
Activate both the lights and perform another render.
If you are lucky you’ll get the correct lighting and illumination, but more likely you’ll have to tweak your light settings to get the result you have in mind.
Obviously the changes your’re going to do will vary depending on the lighting effect you want to reach for your render!
Here's my test:
Don’t worry if some of the areas are overexposed, when we’ll activate the final gather the problem will be almost fixed.
Anyway, if you want you can do a small test: do a region render of the most significant areas of your scene, simply activating the final gather with the following settings: “rays”: 100 “min max radius”: 0/0 and “rebuild photon map” turned off. This is my result:
If you still have problems with over-exposed ares or getting weird artifacts I suggest you to slightly decrease the photons intensity of the spotlight and also slightly decrease the intensity of the point light (mostly if the over-exposed areas are those directly affected by the area light).
Now that the light seems more balanced we’ll start optimizing the GI.
This is the Maya “Caustic and Global illumination” panel.
Here you are some short descriptions of the main GI settings:
- “Global Illum Accuracy”: this value, that we have already set to 512, represents the quality of the photon map.
- “Global Illum Radius”: we’ll set it later. As for now just remember that the default value is 0: with this value mental ray calculates the best setting for the render (in 90% of cases you can keep this setting). Anyway, to optimize our rendering times we’ll hand-calculate it.
- “Max Photon Depth”, “Max Reflection Photons” e “Max Refraction Photons”, are the settings of the well-known photon bounces. They set the number of bounces that our photons will perform before they stop.
The first value indicates the maximum amount of bounces.
Now we have to choose the Photon Volume Radius and the Max Photon Depth. Talking about Depth, I’m getting good results using the default settings (5-5-5).
Remember that higher depth values means more light in the dark areas of your render, but it will also increase your render times.
As I said before, changing the Photon Volume Radius will allow us to optimize our render speed.
You can test it performing a render (GI only) with the Photon Volume Radius set to 0 (best quality).
Have a look at the render times: 50 seconds (on my workstation off course)
Do your experiments increasing the radius value and see how your render-time changes (obviously along with the image quality)
You can start with very low radiuses (1 for example) and increase the value until you get a result similar to the first render (with radius 0), but with lower render-times. Remember that the radius is expressed in local scene units.
When performing these tests turn off “rebuild photon map”, in order to speed up the test renders.
Remember that in this phase even the smaller time gap between your tests could lead to considerably different rendering speeds when working on the final render. So, every second counts!
Here you will see my radius-changing tests:
I chose radius = 15
الجزء 2 ..
في الأسفل ..
طبعا الدرس منقول من موقع أجنبي للفائدة ..
سأرفق تطبيقي خلال فترة قريبة إن شاء الله .
تعليق