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Box colliders not oriented properly with pieces

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ZReeder
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Joined: Aug. 2020
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I'm trying to add a box collider to each piece in my geometry but I'm having trouble fitting the colliders to the pieces.
I'm using a foreach SOP to iterate over each piece and add a collider to each one.

I have tried using the collision_geo group, and a unity_script attribute to add the colliders, and it works well for straight horizontal or vertical pieces. But for diagonal boxes, as shown in the first screenshot, using the collision_geo group causes the colliders to be placed without the correct orientation. And using the unity_script method creates box colliders that fit the pieces' bounding box as shown in the second screenshot.



I have also tried using an attribute wrangle within the for-loop to add a unity_script attribute with parameters to create the colliders via a custom script, but when the asset is built in Unity, the script is called with the exact same values for each piece (which I guess makes sense, since it is a detail attribute, but I'm not sure what the correct way to do this is).

Has anyone found any workaround for this, or know what I'm doing wrong?
Edited by ZReeder - Dec. 31, 2020 09:21:03

Attachments:
collision_geo.PNG (42.5 KB)
boxcollider.PNG (17.0 KB)

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ZReeder
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It was a long, painful process, but I think I have something I can work with now (but if anyone has an alternative solution, please share).
Basically what I did was figure out the rotation needed for each piece and pass the necessary information to a script in Unity which creates a child object with the correct position and rotation.

I attached the thing I was experimenting with. Hopefully it helps someone else because I just wasted most of my vacation on this.

The script for Unity is copied below: (I'm also curious to know if there's a simpler way to pass parameters from Houdini to a Unity script function.)

using System.Linq;
using UnityEngine;

[ExecuteInEditMode]
public class CreateBoxCollider : MonoBehaviour
{
  void CreateCollider(string serializedParams){
    print(serializedParams);
    string[] splitParams = serializedParams.Split(' ');
    GameObject colliderObj = transform.Find("collider")?.gameObject;
    if (colliderObj != null){
      DestroyImmediate(colliderObj);
    }
    colliderObj = new GameObject("collider");
    colliderObj.transform.parent = transform;
    colliderObj.transform.localPosition = ParseVector3(splitParams[0]);
    colliderObj.transform.rotation = Quaternion.Euler(ParseVector3(splitParams[1]));
    BoxCollider bc = colliderObj.AddComponent<BoxCollider>();
    bc.size = ParseVector3(splitParams[2]);
  }

  Vector3 ParseVector3(string val){
    float[] components = val.Split(',').Select(v => float.Parse(v)).ToArray();
    return new Vector3(components[0], components[1], components[2]);
  }
}

Attachments:
collider_test.hdalc (35.2 KB)

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