all_int_lin_msur - Function

Calculates all intersects between a line and multiple surfaces


Description.

This function calculates all intersects between a line and multiple surfaces. It is basically the same routine as all_int_lin_sur() but with the difference that it operates on a set of surfaces instead of one single surface.

all_int_lin_sur() should be used when only one surface is involved and you want to speed up computations by supplying an approximate start value. all_int_lin_msur() does not take a start value as input.

all_int_lin_msur() should be used when multiple surfaces are involved. It will then compute faster than if all_int_lin_sur() was called indivudually for each surface.

Syntax

all_int_lin_msur(sur_in, nsur, p, v, order, nint, uv, xyz, sur_out)

REF	sur_in();
INT	nsur;
VECTOR	p;
VECTOR	v:
INT	order;
INT	nint;
VECTOR	uv( );
VECTOR	xyz( );
REF	sur_out( );

Principal parameters

su_in	- Array of surface id:s
nsur	- Number of surfaces
p	- Line start position
v	- Direction of the line
order	- Method for the ordering of intersect points.
	Ordering is always with respect to the distance to the input R*3 point p    but solution points will be omitted for the different cases.    Eq. 1: All intersect points     Eq. 2: Only intersect points in the v (shooting) direction    Eq. 3: As 2 but only intersect points with surface normals that have the same direction as              the v vector (the shooting direction)    Eq. 4: As 2 but only intersect points with surface normals that are in the opposite              direction as the v vector (the shooting direction)    Eq. 5: As 3 but the number of solutions will be zero ( 0 ) if the first solution   point has a              surface normal that is in the opposite direction compared to vector v (the shooting              direction)    Eq. 6: As 3 but the number of solutions will be zero ( 0 ) if the first solution point has a              surface normal that is in the same direction as the vector v

nint	- Number of output intersects.

Optional parameters

uv	- Array with output (U,V)-values
xyz	- Array with corresponding R*3 (X,Y,Z)-values
sur	- Array with corresponding surface id:s

Example

REF sur_in(2);
INT nint;
VECTOR uv (10);

sur_in(1) := #5;
sur_in(2) := #35;

all_int_lin_msur(sur_in, 2, vec(100,20,30), vec(1,0,0), 2, nint, uv);

Calculates all intersects between the line defined by point (100,20,30) and the vector (1,0,0)
and the surfaces #5 and #35. All nint intersects in the shooting direction are returned in uv.