003 - Materialism 1.5/2

General / 11 March 2018

Hi, In the third post I am going to try to explain what are we doing and why we are doing. And the reason is, tons of people try to create textures, materials and stuff, but they do not understand the core of it, the soul of it.

Achieving photorealism is something comes from the every step of creative process, from the references, modeling, lightning, the props and every single detail. However achieving photographic look is only from the final image, just the final image.

Photorealism is not a step by step thing, or there isn’t any guide to achieve that,  it is an ever-receding ideal.

First of all, we have to understand that, on screen we always look at the object or the scene from a lens. A movie, or a photograph, a game or VFX doesn’t matter, we always look at it from a lens. So as people try to mimic the nature, they forget about the angle people sees it. Photography itself is not nature, it is all seen through a lens and it has tons of distortions, mimicking those is the easiest way to make the image look photorealistic.

We drive so much subconscious information from the image we are looking at even though we are not looking at all the details.  And scale is the biggest and most important aspect of that. It effects the depth of field, the fall-off of the light, the haze, noise in the scene. If you start doing it in scale, later you won’t need to fake it.

And of course with all respect, with a bad or not correct materials, everything can be destroyed. And of course I am not going to talk about material creation in detail, since there are many masters like Grant Warwick, and their tutorials will always be the stonehenges for all of us.

I guess my only suggestion would be never using RGB values close to the maximum and minimum, as a rule of thumb, never exceed 200 RGB for white, or never go lower than 20 for black. This applies for all colors of course. And also maybe desaturating the textures would help a little, since the reflections and sun light with the sky will brighten up the image more than enough. So if you put the real photo as it is in a diffuse slot, you will have twice the saturation you were looking for.

Second most imparting is that, the realism comes from the light, this actually might be the most important thing and it also correlates with the scale. The sun and the sky will have vastly more power than the brightest lightbulb. Weird enough, tons of people always asks me what their scene look so artificial, and without even looking at the image, I ask them did you put all of the lights accordingly and correctly. And they are not even sure. Because most of the time, they do only eyeball the lights, or they see an example and just try to mimic it. Nope, thats not the way, photographers mostly want the natural light, sun, sky and some soft boxes to fill the darkest corners, and yes we will certainly have a lot of overexposed places. Photographers also have those black corners and over exposed places, and yes they do need to deal with these too. But our advantage is their images are 14 stops, but ours 20, so that we can deal with these burnouts easily and get back our information.

Third one, as in the intro I have briefly talked about the camera, we are looking from a lens, so making your lens realistic, will give you better results. And actually not as you might thing, this part is the easiest part. Vray, corona or all major render engines offer physical camera settings like aperture, exposure, iso.

For starters, just go outside and take some photos with auto mod, then you will have some values to start with. Experiment with different skies, and you have a couple of values to experiment.

Then it comes to using the camera. As you are trying to mimic a lens, then you need to understand how a photographers work, how do they see the world, how do they shoot.
That starts from the basics, it is generally bad advice if you hear that, you should only model the parts you are going to see on the final image. Of course if you are on a really tight deadline, it is a life saver, but in general, it is not the best way.

My advice would be to block your scene accordingly, then think like a photographer, walk around your scene, experiment, see for yourself. Then go into more details, then try more angles, views, then go into more details. For the angles or examples, there is always /archdaily/, /dezeen/  to get some inspiration.

So the final would be render settings and image format. A linear workflow will ensure that exterior light fills the furthest corners of your interiors without having to crank up the light beyond reason, producing burnouts or fireflies and other rendering artifacts in the process.

Many artists try to get sharpest image possible, but in reality that is not the case. Even with the best optics and large sensors cannot give you the sharpest image at 100%zoom. Mostly they will have slightly blurred edges, to get this effect having blur filter 2px for 4K render would be sufficient and it will help to make sure everything blends well together.

After this point, I guess we have to talk about post production, which will be after materialism series. So on the next one I hope we are going to talk about creating a material and understanding its features which are fundamental for this process.


002 - Materialism 1/2

General / 20 February 2018

Hi, In the second post I am going to try to explain the logic of creating materials. And the reason is, there are tons of people who are looking at the internet, for preset materials, or textures which almost always ends up with really terrible results. And I am going to try to explain why.

Images are property of ivabox

Before even trying to create anything, we need to understand what is "material" and how do we perceive them.

  • The photons from the light source bounce - reflect from the objects
  • That photons come to our eyes
  • Our eyes can differentiate  three different wavelengths of light, green, blue and red. 
  • Each eye contains around 6-7 million cone cells, which can combine three wavelengths that we perceived and our brain turn them into objects.

So everything starts with the light, and reflection from the object. Then it is easy to say that, we NEED light to see objects, and every single object is reflective (except vanta black, which is %99.9 non reflective - but still reflective).  The other thing we need to focus is, our perception. We need to perceive and understand what we are creating. Just doing it from memory or from the values from the net, most of the time will feel artificial. So here is some pointers:

  • Material creation should always be done by using real-world references. We need a least couple of angles and light conditions of an object to fully understand its properties. If available the best way is to observe the material itself, if not, then trying to find as much photos as possible is the way.
  • Be subtle! This is actually to the end result. Generally overdoing some stuff might help to get to the right results. Like overexposing an object to the light, overusing glossiness, bump or anything. Then when fine tuning, we will find a sweet spot for every object.
  • Nothing is perfect. Using imperfection maps, or changing glossiness maps from the diffuse map is almost always is a must.
  • Do not afraid to compose maps. Its not necessarily to be layered materials, but maybe composited diffuse maps. As nothing is perfect or that pure.

In any render engine, there are TONS! of settings to play with, but the logic of them is actually simple. And unfortunately a lot of people only try to memorize values for certain maps, which is really really wrong. In real world, nothing is same, and nothing is perfect, so in CGI it should be the same situation as well. In the next post I am going to create a nice metal, and a painted metal, so that we can understand how to approach a material creation.


001 - Textures

General / 14 February 2018

Hi, in this blog I will discuss design theories, tips and some points to improve any design - image quality. I make this because I tend to drift from an idea to idea easily. With archiving what I think, I might help myself, and maybe others. If you find something useful or just wanna say hi, please comment. My plan is to post a new post every week.

Tons of people are just looking for the correct texture all over the internet. And most of them thinks that the magic is in the textures.

For me, there are only couple of textures that you really need. 

  1. Dirt maps - imperfection textures: You can get them from tons of places, one of them is to buy Clement Feuillets 2 sets.
  2. Concrete photos: You can just do whatever you want with concrete photos. You can even make dirt maps with these.
  3. Scratch maps: This is a little essential, I am using the ones from cg-source since his textures (also hdri skies) are the best in the market, but you can still get it from tons of places, just like dirt maps.
  4. Wood textures: Especially in Archviz, the clients can ask for really specific texture and tree types, so having an archive for maybe one for every single tree type could help a lot.

And thats it, you do not need anything else. For other simple patterns, (maybe like marbe, asphalt, fabric) you can have couple of patterns, then just change the color and contrast. For example; a fabric, you just need couple of displacement and normal maps, which you can easily make by using debarti capture tool. I mean you can make any texture with this tool. 

Bonus: for 3d props and tons of extraordinary textures, you can always use Megascans. I tend to download couple of materials for their normal and displacement maps.

Before I was downloading every single texture packs I have found on the internet, and now I am only deleting folders after folders. And I'm just making couple of specific ones when needed, and these are the basic steps:

  • Cropping all of the images to their correct sizes and proportions.
  • Check the "white balance" for all the maps.
  • Duplicate the layer and use Filter>Other>High Pass with 100 radius.
  • Edit>Fade High pass with %100 opacity Luminosity, then the texture will get the color it just lost a moment ago.
  • To make it seamless, just use Filter>Other>Offset to move the texture around and just fix the problems with whatever tool you want to use.
  • Image>Adjustments>Match Color tool can fix the color differences.