Scaling Asorted Custom Models

curator785

Hello,

    We have been purchasing 3d Model from different website to use in our project.  Each of these models come with different parameters and we want to know is there a trick or easy way to set a scale so that it is proportion to each other.  We don't want a tank bigger then a person or a plane the size of the map.  Simply asked is there away to scale them in blender that would make it so we don't have to scale them in our game engine every time.  This would include an understanding of how to select the right scale for all of the models.  We are making an RTS with a top down camera.

hansolocambo

I guess you'd have to set a reference object in blender, like an average human. Then import those objects you bought from different sources, resize them according to your reference, then re-export them one by one to a new and proper size. Don't think there's a magic way to do that automatically as many people work without any scale in mind. 
It's gonna be hard to make an RTS that has a "style" with assets from different modelers who didn't work together at all I'm building 3D assets for an Android RTS at the moment. My own issue : it's indie dev and there's no designer. So I have to build 3D assets (fine) and design them ( )
Good luck with your dev ! 
Cheers. 

curator785

Thank you yeah I wish I knew more about modeling I'm a programmer so its new to me.

pior

What you need to be aware of is the concept of "object transformations". For instance, if you import a model into a 3d program and notice that it is opening as 10 times bigger than your reference character, you obviously want to scale it down but you also want to make sure to apply (also sometimes referred to as "reset") its transformations, an operation that basically applies the inverse transformation matrix to all the vertices thus allowing the model to be displayed at the intended world scale even when set to a scale of 1.

You want to do that because if not, the model would carry a x0.1 factor applied to it on export and this pretty much guarantees issues later down the pipeline (for instance this x0.1 factor could affect physics calculations, collision detection, and so on).

Some engines are better than others at dealing with that but regardless, you want things to be as clean as possible in your authoring environment.

Some reading on the topic : 

https://wiki.blender.org/index.php/User:Fade/Doc:2.6/Manual/3D_interaction/Transform_Control/Reset_Object_Transformations

https://knowledge.autodesk.com/support/3ds-max/learn-explore/caas/CloudHelp/cloudhelp/2017/ENU/3DSMax/files/GUID-B98414B9-4F28-45F4-A1F4-9DA994548ED9-htm.html

curator785

Awesome thank you I will review these after work today.

throttlekitty

Just chiming in to say Use the grid, Luke. Once you have a unit size decided, it's relatively easy to start eyeballing and sizing things into the grid lines. Also look into setting pivots on your models- sometimes it's easier to place and size something like a tank or a building if the pivot is in the lower-forward corner rather than the center that you might get from an import.

This got me thinking, is there any "smart bounding box" out there? It wouldn't be perfect for this job, but it would be nice if the bbox volume was based on importance rather than overall size. A walkie talkie or a car both have antennas that aren't important for judging object scale. TBH it's something I've never looked in to but I could see that being useful.

curator785

@pior So based on these link and a little research "object transformations" in this case is setting the object back to default of when it was first created?  Is that what I'm getting from these links?

pior

That's where the terms get confusing. In max it's called "reset Xforms" but it does the opposite of resetting the transformations back to sale 1x : it applies the the transformation, so that the desired visual scale happens when the the object is set to 1x. The Blender terminology makes more sense : Clearing transformations and Applying transformations.

Just try it first-hand in the program, you'll see.

curator785

Awesome thank you very much I will.