Tong
12-07-2008, 11:43 PM
just liked it:
quote
Where ever you start, you have to keep in mind that this is a relation among all parts. We have foremost to deal with the materials, the lights and the -yes- the render-method and the needed settings. IS there a common place that gives you the best setting, I believe not. If so, it would be a preset available. What I try to communicate here is the problem that this question contains.
You use the target description :"very realistic with a nice atmosphere", well, that is a description that would lead ten artists to ten different results. Very realistic is maybe easier to discuss than nice atmosphere, as this is relative.
Sorry for the preamble, I hope it didn't sound de-motivational, but it is needed to understand the complexity of the theme.
Materials. To set up the 'right' materials, you need to be comfortable with the REAL materials that you aim to simulate. Take photos from these materials, take 100s or more, from each angle, and in each light situation. Go close and far away form them with your camera. There is no way around, if you want to have it realistic.
In the moment you know your materials, and I mean literally know them, open the Material Editor and go from the top to the button and check all the channels if there is a need for these channels in your Materials. Mostly underestimated is the Diffuse channel. More than often this channel is ignored and replaced with altered color information. If you understand the difference of color and diffuse, and if you find the differences also in your Reference images, go to the next channels. Some are needed, some are not.
Since few years people discuss if Specular is needed or not, as it can be replaced with reflection - have always the render-times in mind and if a fake is possible or if you need it correct. To have it correct is most of the time a luxury that needs to paid with endless render-times. Finally, if the result looks right - it is right. The study of the channels, is important and there is no short cut. Materials are one step, or one part of the puzzle.
Light. Similar to the Materials you need to study the light-sources that you want to use. Piratically there are only two different groups of light sources, the parallel sources and the radial sources. Well, there are more subgroups and Ambient light is maybe an infinite radial one, but finally it boils down to the two groups. The subgroups of them are e.g. Spot and area light.
Also here, you need Reference images and study them carefully. The settings in one single light source is pretty much endless, and we haven't talked about shadow.
Hint, the Contrast setting is mostly ignored, which gives the light a very specific character, have an eye on that. The Penumbra of the light is a very important information source of an object. Talking about Shadows, means that we have in most cases a fill light in it. Sunlight has mostly a more or less blue tone in the shadow. It is important to mention that our eyes do an automatic white balance, which leads more than often to wrong observations. based on that, we follow what we believe to see and the rendering looks artificial.
Fall off of a light source and many other points, as well as colorization, is a longer theme and can be covered with the study of the parameters.
Material and Light. There is an huge interactivity between Material and Light. Nearly no artificial Light source is white, and with that the colorization of the materials changes. A good understanding of the Color-theory is mandatory to get the balance in your rendering. Why? Because the eye white-balance only the environment not the Image of it. Again, Reference Images!
Light set up vs Render method. Light is not a one ray and stop. The reflection and absorption of a light source in conjunction with the materials is in reality a complex and nearly endless action. This is something that no computer on this planet can digest in an appropriate time, which leads always to simulations of it. To say it plainly, these simulations have always a reduction of the complexity to get the work done. These reductions are covered in the Render-settings of GI for example. But is there only GI the possible answer. Not really, as you can set Light sources in specific positions to simulate the bounce of the light. This needs to acknowledge the material color of the reflective surface and this surface should be excluded from the illumination of the simulation light. (There are more techniques available, but for indoor this is not always applicable, as with Image based illumination based on HDRimages)
This is by itself a longer discussion and you will find as many ideas and opinions about as you find artist in this field. I do not pretend to cover here everything. That would be just impossible. I have started working with light in the '70s and it amazes me that I have even today (this afternoon) 'on set' to think again and again, how to solve a light problem, as I do when I render my 'stuff'. Just place a light here and a light there, but wait, now there is this and that problem. In C4D you can have negative light to solve problems, lights with out shadows, etc.
Suggestion. Besides the endless repeated minimal afford to master this challenge, take reference images, here how to use them after you have studied them: Find a Reference that fits to your needs. Rebuild it in C4D, check the Camera position carefully, then the Materials and the light-sources. Check out what happens if you change this parameter or the other one. If you come close - show it to someone with fresh eyes and ask if it comes close, check the points again and again, if none can tell you which one is the image and which one is the rendering, you have finalized it. Please keep in mind that this is a very high end challenge that you like to do. I have no idea how far you have pushed your skill-level, sorry if I have told you nothing new, but keep in mind that this is for each new project a new challenge. There is no find the formula and apply it needless. The core element is your perception and the way you find the settings for it.
I like to suggest always one book, when I have an introduction class, It is written from Jeremy Birn, Lighting and Rendering [Second Edition.]
This is mandatory, no way around. :•) I have read the First edition in the year it was released and had no doubt to read the second one shortly after release.
I haven't found any parts of that book as being superfluous, and having said that, it show that my little post (little compared to the subject) is just a water-drop of a hot stone and is not even close to be complete. It is also not my impression that I have covered here everything, also, not even close.
Something that I really enjoyed to watch was a DVD from Jeremy Vickery, Practical Light and Color (Gnomon), way too short, hehe, but 2 hours full with well presented information.
Both authors work at PIXAR, and that was fro me reason enough to take time for this information.
After all this, sometimes it is just fun to place some light objects in a scene and let CINEMA 4D just do the rest, but the more you observe you image the more you will tweak it. As someone told me, you never finish an image, you just give up (mostly equally in time with the deadline).
Well, and then comes the theme with Multi-pass in mind, and the post production in Photoshop …
All the best and good luck with the Project
Sassi
quote
Where ever you start, you have to keep in mind that this is a relation among all parts. We have foremost to deal with the materials, the lights and the -yes- the render-method and the needed settings. IS there a common place that gives you the best setting, I believe not. If so, it would be a preset available. What I try to communicate here is the problem that this question contains.
You use the target description :"very realistic with a nice atmosphere", well, that is a description that would lead ten artists to ten different results. Very realistic is maybe easier to discuss than nice atmosphere, as this is relative.
Sorry for the preamble, I hope it didn't sound de-motivational, but it is needed to understand the complexity of the theme.
Materials. To set up the 'right' materials, you need to be comfortable with the REAL materials that you aim to simulate. Take photos from these materials, take 100s or more, from each angle, and in each light situation. Go close and far away form them with your camera. There is no way around, if you want to have it realistic.
In the moment you know your materials, and I mean literally know them, open the Material Editor and go from the top to the button and check all the channels if there is a need for these channels in your Materials. Mostly underestimated is the Diffuse channel. More than often this channel is ignored and replaced with altered color information. If you understand the difference of color and diffuse, and if you find the differences also in your Reference images, go to the next channels. Some are needed, some are not.
Since few years people discuss if Specular is needed or not, as it can be replaced with reflection - have always the render-times in mind and if a fake is possible or if you need it correct. To have it correct is most of the time a luxury that needs to paid with endless render-times. Finally, if the result looks right - it is right. The study of the channels, is important and there is no short cut. Materials are one step, or one part of the puzzle.
Light. Similar to the Materials you need to study the light-sources that you want to use. Piratically there are only two different groups of light sources, the parallel sources and the radial sources. Well, there are more subgroups and Ambient light is maybe an infinite radial one, but finally it boils down to the two groups. The subgroups of them are e.g. Spot and area light.
Also here, you need Reference images and study them carefully. The settings in one single light source is pretty much endless, and we haven't talked about shadow.
Hint, the Contrast setting is mostly ignored, which gives the light a very specific character, have an eye on that. The Penumbra of the light is a very important information source of an object. Talking about Shadows, means that we have in most cases a fill light in it. Sunlight has mostly a more or less blue tone in the shadow. It is important to mention that our eyes do an automatic white balance, which leads more than often to wrong observations. based on that, we follow what we believe to see and the rendering looks artificial.
Fall off of a light source and many other points, as well as colorization, is a longer theme and can be covered with the study of the parameters.
Material and Light. There is an huge interactivity between Material and Light. Nearly no artificial Light source is white, and with that the colorization of the materials changes. A good understanding of the Color-theory is mandatory to get the balance in your rendering. Why? Because the eye white-balance only the environment not the Image of it. Again, Reference Images!
Light set up vs Render method. Light is not a one ray and stop. The reflection and absorption of a light source in conjunction with the materials is in reality a complex and nearly endless action. This is something that no computer on this planet can digest in an appropriate time, which leads always to simulations of it. To say it plainly, these simulations have always a reduction of the complexity to get the work done. These reductions are covered in the Render-settings of GI for example. But is there only GI the possible answer. Not really, as you can set Light sources in specific positions to simulate the bounce of the light. This needs to acknowledge the material color of the reflective surface and this surface should be excluded from the illumination of the simulation light. (There are more techniques available, but for indoor this is not always applicable, as with Image based illumination based on HDRimages)
This is by itself a longer discussion and you will find as many ideas and opinions about as you find artist in this field. I do not pretend to cover here everything. That would be just impossible. I have started working with light in the '70s and it amazes me that I have even today (this afternoon) 'on set' to think again and again, how to solve a light problem, as I do when I render my 'stuff'. Just place a light here and a light there, but wait, now there is this and that problem. In C4D you can have negative light to solve problems, lights with out shadows, etc.
Suggestion. Besides the endless repeated minimal afford to master this challenge, take reference images, here how to use them after you have studied them: Find a Reference that fits to your needs. Rebuild it in C4D, check the Camera position carefully, then the Materials and the light-sources. Check out what happens if you change this parameter or the other one. If you come close - show it to someone with fresh eyes and ask if it comes close, check the points again and again, if none can tell you which one is the image and which one is the rendering, you have finalized it. Please keep in mind that this is a very high end challenge that you like to do. I have no idea how far you have pushed your skill-level, sorry if I have told you nothing new, but keep in mind that this is for each new project a new challenge. There is no find the formula and apply it needless. The core element is your perception and the way you find the settings for it.
I like to suggest always one book, when I have an introduction class, It is written from Jeremy Birn, Lighting and Rendering [Second Edition.]
This is mandatory, no way around. :•) I have read the First edition in the year it was released and had no doubt to read the second one shortly after release.
I haven't found any parts of that book as being superfluous, and having said that, it show that my little post (little compared to the subject) is just a water-drop of a hot stone and is not even close to be complete. It is also not my impression that I have covered here everything, also, not even close.
Something that I really enjoyed to watch was a DVD from Jeremy Vickery, Practical Light and Color (Gnomon), way too short, hehe, but 2 hours full with well presented information.
Both authors work at PIXAR, and that was fro me reason enough to take time for this information.
After all this, sometimes it is just fun to place some light objects in a scene and let CINEMA 4D just do the rest, but the more you observe you image the more you will tweak it. As someone told me, you never finish an image, you just give up (mostly equally in time with the deadline).
Well, and then comes the theme with Multi-pass in mind, and the post production in Photoshop …
All the best and good luck with the Project
Sassi