3D Modeling Standards: Real-World Scale

With regard to scale, a digital 3D model is a funny thing. If the file says the building is 3 meters tall, the model renders the same as if it were 300 meters tall (unless the scene uses scale-sensitive lighting, but most scenes don’t). Scale becomes important only when you merge the 3D model into a scene, a very common practice with TurboSquid customers. If a bunch of merged models are at different scales, the customer has to do extra work to make all the models work together, which involves guesswork (fast, but inaccurate) or time-consuming research to figure out exactly how big that thing is supposed to be.

The number of 3D models at TurboSquid that aren’t at real-world scale is surprising, especially when you consider how easy it is to model to scale in the first place, or to change the scale when you’re done modeling. Most 3D models can be re-scaled quickly and accurately with a few mouse clicks. Models with rigging or dynamics aren’t as easy to scale, but the vast majority of 3D models at TurboSquid consist of geometry only, which responds accurately to scaling.

If your models are already at real-world scale, be sure to mention this in the product description. Customers strongly prefer real-world scaled 3D models over the who-knows-what-scaling-was-used types of models. And if your models aren’t to real-world scale, you can improve your sales by making them so. Check out the videos below to find out how to check and change a 3D model’s scale in 3ds Max or Maya.

Both programs have a default scale. Maya uses centimeters (1 unit = 1 cm) while 3ds Max uses “generic” units that default to inches or centimeters depending on your geographic region (1 unit = 1 in or 1 cm). 3ds Max users that want maximum compatibility for exported file formats are best off using centimeters or meters for scale. In 3ds Max, you can always model in your preferred scale and change it later; if you model in inches, for example, then when you’re done you can change the units to centimeters using the tool shown in the video, and all measurements will convert automatically. Both 3ds Max and Maya also have tools for messing with the way the program handles unit scales under the hood, but it’s a bad idea to change these settings unless you have a definite reason for doing so. If you stick to the tools shown in the videos, you’ll be safe.

Are your models at real-world scale? Do you feel this gives you a competitive advantage at TurboSquid?