VARKON Version 1.15 1997-10-24

eval - Function

Evaluation of coordinates and derivatives


Description

Returns coordinates, derivatives, curvature or curvature directions for a given point on a surface or a curve.

Syntax

eval(ref, case, uv)

REF	ref;
STRING	case;
VECTOR	uv;

Principal parameters

ref	- Identity curve or surface
case	- Evaluation case (XYZ, DRDT, .... See below)
uv	- Parameter point on surface or curve

Optional parameters

None

Return value

A VECTOR equal to the requested coordinates or derivatives.

Example

eval(#5, "DNDU", VEC(0.4,5.9));

Calculates the derivatives with respect to U for the (normalized) surface normal in UV point (0.4,5.9) in surface #5.

All eval cases for a surface

Coordinates and derivatives in surface ##5.1 for U= 0.40000000 V= 5.90000000

uvlocal 0.40000000 0.90000000
patadr 1.00000000 6.00000000

xyz 4078.00145392 295.32866409 3416.25431755
drdu 19.29846079 0.80655928 -4.98459269
drdv -7.74898318 -58.25466669 -60.27168128
d2rdu2 0.05825836 0.00713980 0.22878794
d2rdv2 1.60996519 -12.13643325 12.52153948
d2rdudv -0.02015290 -0.17994164 -0.15624331

normal -0.20225782 0.71704103 -0.66704118
dndu 0.00776220 0.00049559 -0.00182089
dndv -0.03046975 -0.14385945 -0.14540389

kappamin -0.00040019
kappamax -0.00246216
gaussian 0.00000099
mean -0.00143117

r3min 0.96649653 0.03623213 -0.25410960
r3max 0.15803869 0.69608864 0.70034590
uvmin 0.99999897 0.00143358
uvmax 0.27544280 -0.96131746

uvminderiv 0.00143358
uvmaxderiv -3.49008014
angkappa 90.00000000 74.09373413

All eval cases for a surface curve

Coordinates and derivatives in curve ##12.1#1.1 for T= 6.90000000


tlocal 0.90000000
segadr 7.00000000

xyz 4302.12594840 416.49613604 3618.10169318
drdt 52.45042503 0.30346851 -27.72882897
d2rdt2 -0.09881610 -1.15718075 -0.09402066

segtype 2.00000000

prinormal -0.04741811 -0.99379938 -0.10056995
binormal -0.46498396 0.11107038 -0.87832414

kappa 0.00033072
normkappa -0.00032219
geodesic 0.00007463

uv 5.90009346 3.58649697
duvdt 0.99916330 0.25249137
d2uvdt2 -0.00197147 0.00773156



All eval cases for a free curve

Coordinates and derivatives in curve ##15.1#1.1 for T= 13.80000000

tlocal 0.80000000
segadr 14.00000000

xyz 4302.12503127 416.49612945 3618.10217769
drdt 26.22877602 0.15177467 -13.86629445
d2rdt2 -0.01417528 -0.28931755 -0.02908306

segtype 1.00000000

prinormal -0.04741914 -0.99379899 -0.10057334
binormal -0.46498375 0.11107386 -0.87832381

kappa 0.00033073