How would you create your very own realastic textures?

Ok First you need a good digital camera for the main texture from where you will take out all the other textures (diffuse albedo, normal bump, displacement height, specularity, occlusion ). I was using 10 megapixels, old but a good fast 18 megapixels is better for taking nice define textures images. It is important that the digital camera has the ability of taking pictures in poor light, wide angle and excellent zoom. This will let you extrapolate images form far way, fast and from panoramic views. An example could be: Lumix DMC-FZ70 $249.00 Super zoom, over 2 years ago so you can find it used on ebay. (compare: snapsort.com) If you are inspired and you want personal images, take the pictures with a lot of light. Better if there are no shadows and if a cloud passes obscuring the sun , that is the correct moment. Big format allowed you to extrapolate the portion of the wall or target you need. So you need Photoshop or similar to cut and trim the portion you want to tilt and use. Then you need to make a manual process to make much the borders so that when you tilt the image repeating it , the edges match perfectly. In this way you create your very own realistic albedo main texture as a starting point. Remember that there must be no shadow in the texture itself. The resolution can be 32 64 128 256... better 512x512 | 1024x1024 | 2048x2048 | 4096x4096 or a combination, example 512x2048.

If you do not have time you can go to cgtexture now the site is http://www.textures.com/ to look for free ones in a normal nice resolution. But it won't be "your very own" texture. Other but more expensive: gumroad.com/discover | cgtrader.com | joostvanhoutte.com/textures/ | blenderguru.com/product/grass-essentials/ | turbosquid.com/Search/Index.cfm?keyword=textures | etc

Then you need a software for converting the main texture into diffuse albedo, normal bump, displacement height, specularity, occlusion, etc. For this it depends on what rendering engine you are using. If it is Unity, then i suggest a classic software like Crazybump (is not free) that makes the job very well. A better option is a new excellent software: Bitmap2Material 3.0 with much better integration with Unity; although it's not as good as Crazybump when working with final trim. There are other ways like making all the textures in Photoshop with photoshop plugins but you will lose a lot of time.

There are other ways for making the texture; make and use a 3D object and the extract the textures from it. But it is never realistic as making a picture. It's useful only when you need something that does not exist in nature. For example exoplanet, alien skin, abstract materials, etc

Look around in the real world for things that are similar to whatever you're modelling for the game. Take pictures or search Google for references. These days the texture file itself is just one aspect of realism. How much detail can be baked into the normal maps or comes from the amount of polys you can use for that model? Can materials be applied to different parts of the model in the shader? Then that's one less thing the texture map needs to convey. You have to decide what level of detail the texture needs to provide.

A lot of the art here is applying a basic pass of color to the texture layer and then examining the results; iterating and adding more and more detail eventually gets you to the desired result. Then place the models next to other game assets to see if they fit into the same world (it's weird to take Mario and put him into the realistic Los Santos of GTAV because these two games have totally different art directions.) There's the craft of actually creating the assets and then the art of knowing you've created the right assets.

In other words: practice. If you want to get really good go to http://polycount.com/ and check out the works of actual game artists. Read through the threads. Ask questions. Participate and get feedback. There is a wealth of information there on all aspects of game art.

I've bookmarked this awesome site for texture mapping.

Grab an image from a creative commons google search, throw it into this doohicky and voila!

http://cpetry.github.io/NormalMap-Online/