This write-up is a brief overview of the processes used to create PBR textures for a hard surface model with subtle weathering effects. The documentation for most of the popular texture authoring tools does a good job of covering the technical side of things. So the majority of the focus here will be the decision making process that drives the artistic components of texture creation.
All that said, there is one technical thing worth mentioning: The quality of the baked input textures does tend to have an impact on the overall quality of the output textures and the texture authoring experience. Which is why it's generally advisable to identify and resolve any significant issues with the bake setup before moving forward with the texturing.
Check that the UV layout has appropriate padding and textel density. Make sure that any hard edges in the low poly model are paired with UV splits. Try to minimize UV distortion and straighten the UV islands whenever possible. Run a few test bakes then adjust the high poly and low poly models to resolve all of the major artifacts.
Try to keep things as orderly as possible. Take the time to setup a well organized material ID map. Document the baking setup and note when any unconventional shortcuts are used to meet deadlines. This way, if the work is handed off to someone else or if there's future revisions, there won't be a bunch of time wasted trying to guess, remember or reverse engineer whatever process was used to generate the input textures.
Smart materials and masks tend to rely on the input textures for information about the model's surface. So having clean bakes for the normal, ambient occlusion and curvature maps can help make the texturing process a bit easier.
Blocking out the lighting and material values is a good place to start most texturing projects. Look at the reference images and try to create several different lighting setups that match the typical environmental conditions. It's often helpful to have a dark, neutral and bright environment setup. Frequently rotate the camera and lighting setup to check the material values from different angles. This makes it easier to see how the base materials will perform under various in-game lighting conditions.
The material block out is all about establishing the base values for the diffuse, roughness and metalness channels. It's important to work through the material block out before adding any weathering overlays. This is because it tends to be a lot easier to nail the look of clean materials that haven't been obscured by additional layers of environmental build up and damage effects.
Visual identification of specific materials is usually filtered through some kind of evaluative hierarchy: shape, color, reflectivity, physical [damage] state, surface texture, etc. These sort of subtle details tend to be highly contextual and help convey information about what the underlying material is supposed to be made of. Break down complex materials into individual layers and work through the inputs for each of the texture channels.
Ask and answer questions about the physical properties of the object. Use visual cues in the reference images to answer any questions. What is it? A compass. What color is it? Green / olive drab. What's it made out of? Painted metal. What type of paint is generally used? Single stage semi gloss. What condition is it in? Slightly worn. What environmental clues are present? Sandy dust, light brown dirt and grease smudges on flat surfaces.
Additional surface details that weren't part of the high poly model can also be added during the material block out. Things like paint build up around the edges of shapes and fine micro surface textures are fairly easy to add using smart masks and triplanar texture projection. How well the chosen input values and texture overlays represent the actual materials (Metal, plastic, paint, etc.) is an important part of creating convincing textures.
Working through the material block out then adding the major wear states can make it easier to figure out exactly where to place the dirt and grime layers. There's a maxim in the scale modeling community that's something along the lines of "Well sculpted models practically paint themselves." Same sort of logic applies here. Physical surface texture and damage tends to accumulate loose environmental matter over time. So it can make sense to start with the damage layers then add the weathering on top of it.
Effective use of texture details and weathering effects will help an object have greater visual impact and can also be used as storytelling elements. Damage effects can be used to indicate whether something is broken or about to break. Visible repairs can be used to indicate how reliable something is. Dirt, grime and wear marks can be used to indicate how old something is, how much it's been used or how it should be used.
Gather additional reference images of the same object or similar objects in a variety of different wear states. Study the references and note how each type of physical material tends to have it's own unique accumulation and wear patterns. Categorize the types of damage and weathering effects, based attributes like shape or location, then come up with a rough plan for where they should appear on the model.
Smart materials and masks offer a tempting solution to try and add all of these details with just a couple of layers but the results often look overly flat or sort of muddy. Most of the time this is because there just isn't enough separation between the individual effects and it's difficult to control the granularity of how the individual details blend together. That's not to say that things can't be done efficiently. There just needs to be enough subtle difference between things to create the illusion of things building up over time.
Any damage that breaks through a coating should generally be on it's own layer. These layers can be stacked on top of each other and the width of the masks can be adjusted so it reveals subtle steps in height difference between the paint, primer and bare metal. Putting each type of unique damage effect into it's own layer not only makes it easier to adjust each element independently but it also helps simulate the built up appearance that tends to happen over time.
Start with the clean base materials. Add wear through damage that reflects how the object contacts or interacts with the environment and any moving parts. Once the primary damage pass is complete, the weathering layers can be added on top of the existing materials.
These weathering layers can be made up of wet or dry materials like: oil, grease, paint, water, dust, dirt, lint, sawdust, metal shavings, environmental particulates, etc. It can make sense to start with a subtle layer of semi-wet materials, like accumulated grease, since this will help inform where the next set of dry layers should stick to the model.
Wet material layers can also be used to suggest how other entities interact with the object and communicate their relative scale. Under harsh conditions or in the presence of certain environmental conditions there may not be any clear shape signatures like fingerprints. This is because grease and oils usually mix with environmental elements like dirt and are easily disturbed by interactions with things like cloth, plant material, plastic coverings, water immersion, heat sources, etc.
It's important to have subtle variations in the roughness values. When the object is viewed from a distance the individual materials should have a relatively uniform appearance but when viewed up close or under specific cross lighting conditions the other materials present in the weathering overlays should become more apparent.
After the first wet weathering pass is added, it makes sense to add a few broad layers of dry weathering materials. Preferably in contrasting colors, with a darker base and lighter accent layer on top. The base layer of dirt is usually wider than the accent layer. Each of these contrasting dirt layers should generally target different areas of the model to provide some visual interest but there should also be some areas where they overlap to maintain chronological continuity.
Another wet weathering pass provides some additional visual interest and should generally be a more fluid material like oil. The glossiness of this second wet layer can be moderated with another subtle dry pass and accented with clumps of dirt, lint, fragmented plant matter, etc. These final dry layers are mostly used to break up the larger patches of accumulated weathering materials and provide a visual break or bridge between the various weathering layers.
Layers of dust, dirt and other particles can be used to hint at the presence of certain environmental conditions in the game world. Multiple shades of dirt with different grain compositions can be used to suggest that the object has been to multiple geographic locations. Strongly emphasizing just one type of dirt is a good way of communicating the idea that the object has only been to one location or that it's been stored for a long period of time.
Dirt and dust tend to accumulate in corners, behind shallow ridges and on or near wet areas. Each type of material used in the dry weathering layers will tend to behave differently. Three basic shades of dust [dark, neutral and light] and a few variations of dirt particles should be enough for most basic projects.
In this example, the subtle dust layer is a darker color and it accumulates on the flatter surfaces. The heavy dust layer has a slightly brighter color and collects around the tighter corners. These contrasting dust layers blend together around transitional areas and certain flat spots that are partially cleaned by regular use. On top of this first set of dry weathering layers is another wet layer with oily smudges and some partial finger prints. This suggests that the object is used often in an outdoor environment.
A very thin layer of fine dust gets caught behind the subtle ridge of paint around the edges of the shapes. This thin layer of dust has a slightly lighter color than the heavy layer of dust and just provides some visual contrast that helps outline the shapes. It's also useful for breaking up the monotonous tones of the first dry weathering pass.
The smaller void shapes are partially filled with a crumbly looking dirt that's lighter than the rest of the dry weathering layers. This contrast helps draw attention to these areas and also suggests that it's recently been to a place that's completely different from the previous environment. A top layer with small dust speckles helps cover the areas between the dirt in the corners and the patches of dust that accumulate on the flat surfaces. This helps unify the dry weathering layers and the size of the particles also provides a scale reference.
When creating multiple assets for the same game world, it can be helpful to develop specific rules for the weathering layers so everything is fairly consistent. On this project the older layers were darker and the newer layers were brighter. There's also a visible difference in the brightness and glossiness (sharpness of the reflections) on the different wet layers. Which helps suggest the age of the materials, since the more volatile components have evaporated off with passing time.
It's also important to test the combined weathering passes under various lighting conditions to make sure everything will behave correctly in-engine. This will help ensure that everything has a cohesive look and that none of the individual layers have material vales or texture patterns that break the immersion. Most of the subtle micro texture variations in the normal and roughness channels should be barely visible under regular conditions. Only under the right lighting, when the camera or environment lights hit at glancing angles, should some of these details become visible.
Diffuse colors that are relatively close together can make it difficult to spot some of the finer details. As the lighting rolls across the surface it will pick up on the different values in the normal and roughness channels. Which can help enhance or suppress the visibility of certain details. This can be used to create a layered look where only certain weathering elements will be visible at any given time. Which can help harmonize the different layers so they blend together in a cohesive way that doesn't appear too stylized or artificially flattened.
Under more diffuse lighting conditions, where everything is evenly lit, the differences in the roughness values should be fairly subtle. Equipment that looks like it's been dragged to hell and back is it's own aesthetic category but reality is often a bit more muted. Especially when it comes to precision instruments or something that needs to be properly maintained so it will function reliably. The weathering cues should match the game world's back story and the wear level should match the age of the object and it's intended use. Just because they're storytelling elements doesn't mean they are the entire story.
Previous lighting breakdown: https://polycount.com/discussion/comment/2764276/#Comment_2764276
Hello! I pass you my last work I hope you like it!
Taking a crack at it. This is my first time doing an environment off of concept art like this, and my first time doing any kind of environment in, like... 6 years? Should be fun!
Shameless crosspost
https://polycount.com/discussion/229325/tom-hardy-likeness
More videos and stuff on Artstation:
www.artstation.com/artwork/X1dWQY
My brush setup. To be fair, 95% is done with TrimSmoothBorder brush with a square Alpha (Alpha 28 (standard in Zbrush)) the base is done however by duplicating some cubes around, Dynameshing them together, and sculpting the base shapes with ClayBuildup, Move, TrimLasso and TrimSmoothBorder
I actually really enjoyed this that I added it to a list of tutorials I want to make for my YT channel (Proper full guide)
Thanks ! I'm always happy to bring some help to the table =D
Here are some more progress on Jedi assets :
(last one is my personnal favorite =))
Made a very basic blockout to get layout and proportions outlined also wanted to test lighting and fog in unreal. Think I'm next going to try making a large texture that most of the textures will be based on and see how successful this can be before doing much more modelling. Trying to create it starting in zbrush and pulling the export to substance painter. If its large enough Im hoping to be able to scale uv's down for foreground models and avoid obvious repeating patterns this way, also needing less tiling for background models.
Pleased with the red squares in the background, took me a while to get the effect I wanted, though I may go in and add some red lights manually as I used emissive to get a flat colour across the models.
This is my starting blockout for the stylized prop.
Over the last year I've tried to learn how to model for games on my own, and to be honest more often than not I find myself frozen with analysis paralysis, not knowing where to go next, which tutorial or project to make in order to build my portfolio. So I remembered about these challenges, which are a great way of overcoming that. So... hope I can learn a lot from you guys!
My attempt at Cara Delevigne's likeness in her game-ready version :)
https://polycount.com/discussion/229529/cara-delevigne-bust-real-time#latest
https://www.artstation.com/artwork/Le8WXP
Its finished 😁 Thank you so much to every one who commented and helped me, I feel so happy that this is finally complete!
Check it out on artstation https://www.artstation.com/artwork/4XRO9W