UV to mesh with matching prim area

[bbentley81]

Hello,

I am working on a marvelous designer to Houdini pipeline and I have hit a snag that I am hoping someone could help me with.

I am trying to take the draped model and flatten it to the uvs that come out of MD. This part I have working with a point wrangle with "@P = @uv;"

The part I am having trouble with is matching the area. I have tried: 

1. make a measure sop set to area on both the draped and flatted model

2. promote the area attribute to detail using sum to get the area for the entilre model

3 get a scale factor by drapeArea/uvArea

4. use this in a point wrangle to scale the @P by the scale factor.

float currScale = detail(0, "area", 0);
float targetScale = detail(1, "area",0);
float scaleFactor = targetScale/currScale;
@P *= scaleFactor/1000;

This, however, is not working. I am not sure if it is a problem with my math or my logic. If anyone can shed some light on this I would be greatly appreciative. I have attached an example hipnc file for reference.

Cheers,
B

 

matchArea.hipnc

[anim]

1 hour ago, bbentley81 said:

This, however, is not working. I am not sure if it is a problem with my math or my logic.

math, since you are dealing with areas, which are quadratic, to compute linear scale you need to do sqrt() 

float currScale = detail(0, "area", 0);
float targetScale = detail(1, "area",0);
float scaleFactor = sqrt(targetScale/currScale);
@P *= scaleFactor;

[julian johnson]

@P *= sqrt(scaleFactor);

I think if you double the scale of something you quadruple its area...

Edit. As Tomas just said!

Edited February 10, 2019 by julian johnson

[bbentley81]

YAAAASSSS!!

Thank you so much. This worked perfectly!! I've attached the working file for those few who are interested.

matchAreaSqrt.hipnc

Edited February 11, 2019 by bbentley81