Be(aware) of scale in Blender

ZeroDean · January 20, 2024, 5:38pm

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The scale of Blender’s default objects often throws off people’s sense of scale. While this isn’t terribly important when “doodling” it can have a huge impact if you are a 3D content provider or an addon developer or tool creator.

When your creations are real-world objects and/or intended to work at real-world scales, but are built at scales using the default cube as a standard and not the size of objects that humans typically interact with, it can yield unexpected and adverse results.

In some cases, Blender’s default values (such as Collision Margin sensitivy in physics which is set at 4cm, for example) can also lead people astray.

Always working at real-world scale means your creations will work for other people who work at real-world scales (which is most professional pipelines, for example). It is also extremely important when it comes to physics and simulations. For example, soup in a bowl does not behave the same as water in a pool or waves in an ocean. And a standard sized 14mm marble does not act the same as a 2m sphere - especially with Blender’s default values (because meshes won’t be able to get within 4cm of each other).

Working at real-world scale is the only way for all Blender users to get consistent results. It means assets are compatible with an existing standard (and usable in professional pipelines), user-inputted values provide expected and consistent results, and much more.

If you use an addon, material, asset, or anything in vanilla Blender, or anything else and it doesn’t work as expected at a realistic scale, be sure to let the developer know.

Be(aware) of scale or life-sized Suzanne will haunt your dreams.

BONUS TIP:

One of the other things besides objects for scale reference that my startup file contains is a plane with a grid pattern. Why? Because I can easily tell at a glance that this fox model I made, for example, is approximately 8 inches wide. Of course, if you want to be civilized, you can use the metric system.

Another very cool thing about using a grid pattern is that it can help you judge refraction and transparency when working with materials. Plus, if you do it right, it just looks cool.

*Flipped normals are another big issue that I’ve written about here.

thorn · January 20, 2024, 5:54pm

Great advice. I’ll also add - lights and shadows appearance in Blender also very much can be affected by object scale. I learned that the painful way.

ZeroDean · January 20, 2024, 6:11pm

For sure! And thanks.

It drives me nuts when I see video tutorials where the person casually cranks up a light to 5,000 watts to light something. And then maybe add another! This immediately lets me know the scale of their scene is way off.

Perceptually the wattage of lights as an output of lumens isn’t intuitive. But still, if you think about how much light an old 60 watt conventional bulb gives off, setting something to 5,000 should seem excessive.

“The recommended wattage for LED stadium lights for football stadiums is between 400 and 1500 watts.” Of course, they use multiple lights, but it kind of makes a point…maybe!

Musashidan · January 20, 2024, 6:35pm

SSS is also another thing that’s highly dependent on scale. Yes, these things can be cranked up or down, but it is definitely good practice to work in real world scale.

The issue I have with Blender’s scale is that I often get horrible viewport artefacts like very bad aliasing and Z-fighting if I change the scene scale to anything other than the default of metres - for example, working in mm on 32mm miniatures.

Helmut_S · January 20, 2024, 6:37pm

Right you are … but wait until the first Blender power user comes along to tell you how you have to upscale everything by factor ten or more, in order to make cloth or rigid body physics work.

ZeroDean · January 20, 2024, 6:52pm

Some people will say scale doesn’t matter… and it doesn’t in a vacuum. People can crank things up and down all they want to get the look and results they want… and it doesn’t matter if they are pleased with the end result.

But it does matter if the content created is ever intended to be shared with anyone (and this includes tutorials). Because without an accurate scale, the values of pretty much everything are completely off.

People creating content to save other people time who don’t work at real-world scales end up costing those people time if they have to adjust the scales and values of everything in order to get it to work at real-world scale.

I recently purchased a geometry node based container maker (glasses, bowls, etc) simply to see how the nodes were setup. And all the values were based around the geometry of the default cube. So glasses exported by this tool were over twice the height of a typical human. Trying to dial down the numbers wouldn’t work because it was too many different values to manipulate and changing one thing to be accurate would totally mess up something else. I contacted the seller and they said they knew, but they didn’t catch it until it was done and now they have to start over if they ever find the time. It was only a few dollars and I just wanted to see the node setup, so no big deal to me. But this is a paid product intended to save people time.

So it’s better to just be mindful of and work at real-world scale to begin with if there is any chance you are going to share your content or try to teach others how to use blender. That shouldn’t be controversial, but I’m sure it is.

Musashidan · January 20, 2024, 7:21pm

Yes, what you describe is terrible practice. Working to scale is always one of those basic ‘best practices’ guidelines in 3D, for all of the reasons mentioned above. I believe that a large part of the issue is that there are so many artists now creating paid content and a LOT of them have either never worked in a professional pipeline or are hobbyists used to just doing whatever they want. Any artist working in the industry is going to be delivering assets to correct scale purely by instinct.

I personally work with physical printed/cast models so I’m always working to exact scale. Especially for clients that I supply sculptures for casting. The mm tolerances are extremely strict.

ZeroDean · January 20, 2024, 7:56pm

Blender users are truly a generous & enthusiastic community. Which is awesome. But I do think that the nature of this free software and its historic lack of use by professionals and in professional pipelines until modern times (it is picking up a lot!) has resulted in a general hobbyist workflow mentality and not a professional one.

By this, I simply mean that hobbyists tend to do whatever they want (as you say) whereas those with professional experience tend to abide by professional standards. I am not using “professional” as an indication of quality, only as an indication of strict standards (values, scale, pipelines…) consistency and interoperability.

I also agree with what you say about a lot of Blender users creating paid content now. And that’s also great for those who can afford it. But because it is often created by individuals (which is also great) and not companies, when it comes to support you have no idea whether after you pay for a product you will get any support. You also don’t know whether the person on the other end is a super young Blender genius who doesn’t have any professional or professional pipeline experience or someone who has loads of professional experience and will accept & deal with feedback based on that experience. So you kind of have to take what you get.

ZeroDean · January 20, 2024, 8:03pm

Oh man, I just checked out your artstation gallery. What an impressive collection of work! I love it!

I recently spent 13 years away from the gaming industry without ever opening a 3D app before I started learning Blender in the summer of '22. Then I took an unexpected 9+ month break last spring and only got back into Blender again recently. I had to relearn some things and refamiliarize myself with Blender’s quirks, but it was easier this time.

My point is I don’t have much of a modern portfolio to show. Especially as I’ve spent more time running down rabbit holes learning cool things than I have in actually producing art… but I’ll hopefully be on my way to it again soon. I love this 3D stuff. And your work is inspiring.

Musashidan · January 21, 2024, 2:59pm

Cheers mate, very kind of you to say so.

Welcome back! Great to hear that you’ve rekindled the passion for 3D. The constant learning is the beauty of it. A lot of things have changed in those 13 years you’ve been on hiatus. Best of luck with your renewed journey.

Musashidan · January 21, 2024, 3:02pm

Of course, yes. I would always advocate best practices/standards, whether hobbyist or pro. It simply makes our lives easier, and is obviously expected when working in a team/pipeline with strict delivery guidelines.