RoomPlan: Use the transform and dimensions to generate 4 corner points

I'm trying to use data returned from the RoomCaptureSession delegate to draw four corners of a door in SceneKit.

The CapturedRoom.Surface class has Dimensions and Transform members.

I was told in the WWDC 2022 RoomPlan Slack lounge:

"You can use transform and dimensions parameters to draw lines. The 4 corners can be inferred from those 2 parameters: the first column of the transform is the "right" vector, and second is the "up" vector. The fourth column is the position of the wall/door/opening/window/object Combining those unit vectors with the dimensions vector will give you the corners."

So I think this is a basic vector question. I'm not sure what is meant by "Combining those unit vectors with the dimensions vector". I've tried a few things, but I'm not sure how to go about this.

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So this is how I pulled something of kind of quick and dirty.

The dimensions vector is [width, height, length]

And the central point of the door can be defined as: Point(door.transform[3].x, door.transform[3].y, door.transform[3].z) 

I'm seeing the length come up as zero for doors. 

So I defined the upper left point as: 

upperLeftPoint = Point(centerPoint) 
upperLeftPoint = upperLeftPoint.translate(rightV.negate(), doorWidth/2) 
upperLeftPoint = upperLeftPoint.translate(upV, doorHeight/2)
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mike.normal13
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  • HI Mike,

    Can you please explain more on this what type is "upperLeftPoint" and why you negate() right vector only and why first calculating the central points?

    —
    cprabhuu
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So this is how I pulled something of kind of quick and dirty.

The dimensions vector is [width, height, length]

And the central point of the door can be defined as: Point(door.transform[3].x, door.transform[3].y, door.transform[3].z) 

I'm seeing the length come up as zero for doors. 

So I defined the upper left point as: 

upperLeftPoint = Point(centerPoint) 
upperLeftPoint = upperLeftPoint.translate(rightV.negate(), doorWidth/2) 
upperLeftPoint = upperLeftPoint.translate(upV, doorHeight/2)
Posted by
mike.normal13
Up vote reply of mike.normal13 Down vote reply of mike.normal13
Post marked as solved

  • HI Mike,

    Can you please explain more on this what type is "upperLeftPoint" and why you negate() right vector only and why first calculating the central points?

    —
    cprabhuu
Add a Comment