Separate a building in two parts with a curve

[DonRomano]

Hey everyone, 

I try to separate a building using a curve, to drive an rbd simulation, but I'm struggling a lot : 

Here's what I get when I try to separate the building pieces in two parts using a wrangle node, I've written : 

vector pos0 = point(0, "P", @ptnum);
vector pos1 = point(1, "P", @ptnum);

if(pos0.x > pos1.x){
    setpointgroup(0, "right_side", @ptnum, 1, "set");
    }
else{
    setpointgroup(0, "left_side", @ptnum, 1, "set");
    }

But the separation is not following the curve, and I don't really know where I miss something. If anyone has another method or the solution, it will be much appreciated ! 

 

Cheers,

[Lucy Coleclough]

so it looks like you're comparing every point on the building to a point on the curve with a corrosponding point number.

This won't work unless you put some work into somehow co-ordinating the point numbers beforehand.

What I would do is look for the closest position on the curve geometry using:

int prim=0;

vector primuv={0,0,0};

xyzdist(1,v@P,prim,primuv);

this will give you the closest prim and the position on that prim. then use:

vector nearPos= primuv(1,"P",prim,primuv);

to interpolate the point positions on the prim to that primuv location. then compare the current position with the nearestPosition:

if(@P.x> nearPos[0]){

setpointgroup(0, "right_side", @ptnum, 1, "set");

}

else{

setpointgroup(0, "left_side", @ptnum, 1, "set");

}

 

This setup will only work in one plane, currently the x axis.

To expand it and to prevent against looping curves you could look into using a cuttting plane and then analyzing the dot product of the nearest faces normal.

[DonRomano]

16 minutes ago, ColecloughGeorge said:

so it looks like you're comparing every point on the building to a point on the curve with a corrosponding point number.

This won't work unless you put some work into somehow co-ordinating the point numbers beforehand.

What I would do is look for the closest position on the curve geometry using:

int prim=0;

vector primuv={0,0,0};

xyzdist(1,v@P,prim,primuv);

this will give you the closest prim and the position on that prim. then use:

vector nearPos= primuv(1,"P",prim,primuv);

to interpolate the point positions on the prim to that primuv location. then compare the current position with the nearestPosition:

if(@P.x> nearPos[0]){

setpointgroup(0, "right_side", @ptnum, 1, "set");

}

else{

setpointgroup(0, "left_side", @ptnum, 1, "set");

}

 

This setup will only work in one plane, currently the x axis.

To expand it and to prevent against looping curves you could look into using a cuttting plane and then analyzing the dot product of the nearest faces normal.

Thank's a lot, works perfectly !