使用opengl渲染围绕3d对象的框架

Question

I am rendering a 3d Object using Rajawali and Opengl on android. I want to render a cube around boundaries of the object in exactly the same as shown.

I understand the I may need to use a set of lines or the stack api in rajawali. But I dont understand how can I use the Object3D api to figure out which points consists of the line. I tried using Object3D.getGeometry().getBoundingBox() api but its returning null.

I need hints on how can I derive the min max Number3d points using Rajawali api and whether it would be the right solution to create a set of 12 lines based on those lines. Or should I somehow augment it into the Model after loading so that i can scale around with it?

This may be too obvious but please consider me a beginner. Thanks.

Answer 1

Object3D.getGeometry().getBoundingBox() return undefined value until you call Object3D.getGeometry().computeBoundingBox() method which updates the bounding box information.

The Answer below will give you more information if you are using complex 3d objects with scene hierarchy. Any way to get a bounding box from a three.js Object3D?

Update: The best way is to create a separate object with lines using Min/Max values and use the original object's Transformation. Or make the BoundingBox geometry a child for the original object.