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The Top 10 Blender Material Mistakes and How to Fix Them

Mar 5th 2024

Creating good materials doesn’t have to be too complicated, but it also isn’t a topic to breeze past because, if it’s done wrong, it can really make a render look fake or boring.

I’ve seen hundreds of exercise submissions for the Fundamentals of Materials and Shading course and many more beginner renders from my time as a teacher. To be honest, I can sometimes copy and paste feedback because so many people miss the exact same things. In this article, I’ll show you what mistakes to avoid so that, even if you are a beginner, you can improve your renders right away.

Not using roughness textures

The most commonly neglected texture type by beginners is the roughness texture.

oughness_compare.jpg

Even if you have your base color and your normal or bump map all set up, your material can still look flat. Adding a roughness map is a great way to fix that! Even just some basic noise might help.

noise-roughness.png

Procedural noise is a great simple setup, but for even more detail, try using an image texture. Also try smoothing things out where the object would be grabbed or poked, or where the roughness would get rubbed away by contact with other objects. If your object is used by humans, don’t forget fingerprints!

When in doubt, always use a roughness texture.

Not picking the right base colors

Colors that are too saturated used to be a problem, but thanks to AgX, Blender’s new default view transform, it’s generally fine.

One thing I will say though is that always using bright colors makes less use of the full dynamic range. If you’re used to having the value close to one on all your colors, try setting that to 0.5 for most things and then you’ll be able to selectively push one or two materials all the way to 1 and make them pop even more in the same lighting conditions.

r-scheme_example.png

One thing to avoid is using the same base color for different materials. Add some variation, and even within materials, add some variation per object or even per mesh island.

Another tip here is to use a color scheme just like a designer if you want your materials to really go well together. When in doubt, try using color.adobe.com for finding matching colors and inspiration.
Also, try using gradients instead of just flat colors. Kent does this in his Cubicity course and it makes even just the simple colors way more appealing.

Using too much bump instead of geometry

Bump maps and normal maps can give the illusion of detail on a surface, but when the illusion is pushed too hard, it starts to break down and looks pretty bad. So, how much is too much? Well, if a detail should be casting a shadow or breaking the silhouette, it should be geometry instead. Whether that can be micro displacement or should be manually modeled depends on the situation but keep the bump subtle and use real geometry if you need to push it further if at all possible.

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One related tip is that if you’re creating your own bump map, try blurring it a bit. The more of a gradient there is in the texture the more it’ll appear to pop out.

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Also, try using an absolutely miniscule amount of very soft bump to warp surfaces so that they’re not totally flat. A noise texture is good for organic materials and Voronoi with smooth F1 is good for things like metal.

Not adding proper wear and tear

3D renders look clean right out of the box, and it’s important to mess with the textures a bit to add some believability. Now, you can also go too far and get a cheesy, overly grimy look, which you probably also don’t want.

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How do you get it just right? Well, try keeping any procedural placement of grunge pretty subtle, and then paint a mask to manually control where it’s strongest. Look at reference and see where it would come in contact with objects, people, or the elements. Usually procedural grunge is generic, which makes sense because it needs to be used in a wide variety of situations, but adding in more details that are highly specific to the object and its context will go a long way.

It’s pretty fun to over-grunge an object, so I’ll often do that and then tone it back down a bit. A few good effects to have in your back pocket are dirt, smudges, scratches, and dust. You can add or subtract these masks from each other, as well as ambient occlusion and the up or down surface normal, to combine them all in a way that makes sense.

Not using high quality textures

Zoom too close to any texture and it’ll start to break down. You don’t need to use 4k maps for everything but try to make it so that each pixel of the texture is at least smaller than a pixel in the final render.

Luckily, there are more places to find high quality textures online than ever. Many do cost money, but it will likely make a big difference in the final result.

I always check PolyHaven first since they’re free, and then the Blender Market, Game Textures, Substance Source, and Poliigon.
Nothing kills the quality faster than a low-res jpeg or a texture that doesn't quite match, so it’s usually worth it.

low-res_compare.jpg

One trick to getting the most out of textures is, if you do still need to zoom in pretty far, set the interpolation to Cubic so you don’t see the individual pixels and then overlay just a little bit of a tiled texture or procedural pattern to give it more detail up close.

Not using SSS or translucency

Most objects have at least some light that scatters beneath its surface. In fact, the light bouncing around just under the surface and then coming back out is exactly what diffuse materials are approximating! Subsurface Scattering, or SSS, is just a more physically accurate diffuse shader. 

Diffuse shaders are really fast to render and look good enough in a lot of cases, but when the light hits a sharp angle, you may want some of that to actually pass through.

sss_compare.jpg

For really hard objects or objects far away it’s really not necessary, but even a tiny amount of subsurface scattering can really bring out the best in close up shots of plastic, resin, cloth, jade, thin wood, or anything that’s soft to the touch.

Subsurface scattering is only useful for objects with thickness, so for objects that have no thickness like leaves or paper, use translucency instead and mix it in anywhere between 0 and 0.5. The Principled BSDF doesn’t have a translucency option quite yet, so it’s something that needs to be done manually, at least for now until it gets the thin sheet mode.

Having obviously repeating textures

Tiled textures are amazing for covering large areas, but they don’t look good if they’re too obviously repeating. To fix this, try using larger secondary or tertiary textures to vary their hue, saturation, or value over larger areas.

You can also use vector scattering to randomize the textures over the surface. I made a whole video on this technique, or you can download the Scattershot add-on which will do it for you in one click. Another technique which is built into scattershot is taking several similar tiled textures, randomizing them, and then blending them together with noise so that there’s as much variety as possible.

Having obviously procedural patterns

Blender’s built in patterns are great building blocks, but they’re not necessarily great final results. Procedural texturing can be an amazing way to add details to a surface without needing to mess with UVs, but there is a bit of a learning curve if you’re building them from scratch. The trick is to make them look like they’re not procedural by adding plenty of variation and creating shapes that match reference.

Most beginners make patterns that are too evenly distributed, without layers of detail, and with too much contrast.

The main key is to learn to use the color blend modes (and eventually just math when you get more advanced) to mix several procedural textures together as well as manipulate the vectors to get the complex shapes that you need.

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Both Kent and I have spent many, many hours teaching this subject, so if you’re interested in following along from beginner to advanced procedural projects in Blender, check out the Fundamentals of Texturing, Sessions, and Shader Forge courses on CG Cookie.

Having incorrect proportions

Having incorrect proportions is by far the #1 modeling mistake I see, but that can be just as much of a challenge when texturing. The size of details tells the viewer the size of the object, so if they’re too big or too small, the whole thing will feel off even if the viewer can’t put their finger on why. While this happens most obviously with details like screws and anything with text, it also comes through in the size of dirt and scratches. So, always double check proportions.

orbot_0200.jpg

That said, you don’t always have to use textures for exactly what they’re intended for. I’ve often used a moss texture to vary the color of a landscape that’s farther away or squished a marble texture to fake wood in a pinch.

The proportions for those are obviously off, but the trick is for it to be so different and cleverly disguised that the viewer won't recognize it for what it is. So, do get creative with how you use your textures, but also look at a lot of reference material and use that to judge whether things look to scale in your render.

Improve the context

One of the first beginner material questions I reliably get, is why isn’t a material that has a low roughness looking shiny? Well, that’s because it doesn’t matter how reflective something is if there’s not much around it for it to reflect. And how the light plays across the surface can’t be seen if the surface itself isn’t very interesting. While this may seem obvious to some, taking a second to think about it can be helpful for improving the look of the materials in any render.

A shader can only be as good as the surface and the context allow it to. Lighting is incredibly important, and so is modeling. Modeling can be challenging, and so many beginners jump right to materials and lighting without polishing the geometry as much as they could. Often, materials do not need to be over complicated and instead need better geometry to sit on.

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Also, Eevee is great for many things, and Eevee Next is shaping up to be an amazing update, but there’s no substitute for good old-fashioned path tracing that looks great out of the box. Even Unreal 5, with all its incredibly impressive real time tech, can’t match the pure visual fidelity of a fully path traced scene.

I use Eevee all the time for projects where speed is more important than quality or for stylized renders, and I absolutely love it for that, but when I really want my materials to look their best, I always use Cycles. This is especially true of anything that uses subsurface scattering, refraction, emission, sheen, or complex lighting, and really anything besides the basics.

So, if you want your material work to stand out, don’t be too cheap on the render times!

Author

Jonathan Lampel
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