Join Ryan Kittleson for an in-depth discussion in this video Checking and changing a model's scale, part of Meshmixer: Additive Manufacturing Job Preparation.
- [Instructor] Strangely, many 3D model formats don't include metadata about what unit of measurement it's using. So if a model is five units tall, you might not know if it's referring to inches, millimeters, or centimeters. Meshmixer has some tools to help us see the model size and to set the units or change the size. Let's see how it's done. Okay I've already got my exercise file imported, and before I start messing with the scale, I'm actually going to rotate it so it's properly aligned in the scene.
Sometimes this can happen, Meshmixer might interpret the orientation of the model differently than the program that exported it. So for this I'm going to hit T to get into transform mode. And let's just go ahead and click on the rotate, drag this down. If we bring our cursor out to these notches, it'll snap to five degree increments. So, let's bring this to 90 degrees and also I'm just going to bring it up a little bit so it's sitting roughly on top of the plane here. And we can turn off snapping by turning off S here, and now it'll slide without snapping to increments.
Okay, great. Let's accept that. Now let's go into units and dimensions. Hit U on the keyboard. Okay, here we get a little bounding box around the model. It tells us how big it is in each dimension. So, let me just move my view around here so we can see all of these. So you can see it's 67 units tall, 56 deep, and 58 wide. Now Meshmixer by default interprets all units as millimeters. Which is pretty useful in this case, this is actually the size in millimeters that I want this to be. However, if you actually meant this model to be in inches or centimeters, you're going to have to change this.
So one way to do it is by clicking on the unit, and we can come down and change it to any different measurement we want, let's say inches. Now when we select a different unit, it asks us if we want to keep the X, Y, Z, the same? That means interpreting this now as 58 inches, 67 inches, and so on, or, converting it to inches. So converting this from millimeters to inches. Let's see what happens if we click convert. Okay now you can see that in inches it is now about two and a half inches tall.
If we'd clicked on the other option to keep these units the same, then we would have a model that's 50 to 60 inches tall, and that would be a little extreme. We can also change the scale in here. So, if we just click and drag on these, we can change the scale up or down, and it's snapping to half inch increments. So let's actually turn off snap here so we can just set this to anything we want. So I'm just going to scale this up or down, where ever you want it to be. Or you can come in here and click on this, and just type in a new number.
So let's say five inches. Okay when you're happy with the size on the units, go ahead and click on done. Okay, so now we've got our units and our scale set. Because of this ambiguity with a lot of 3D models, not knowing what the units are stored in the file, I try to save the appropriate scale and units in the filename. So the name of this file was dewhopper.ply, but if I'm going to save this out, I would add in let's say something like dewhopper five inches tall, or whatever the unit and scale is that you've chosen for your model.
And this is because a lot of times software will incorrectly interpret the scale or the units of a model, and so having the correct information right there in the filename can help you know how big a model should be, no matter what software you open it in. And now you know how to make these changes in Meshmixer.
This course was created by Ryan Kittleson. We're honored to host this training in our library.
- Checking and changing a model's scale
- Fixing mesh issues
- Checking a model's balance and adding a base
- Splitting a model into smaller pieces
- Making tab and slot connections
- Increasing thickness for printability
- Making a model hollow
- Exporting a model ready for printing