Пример любой: вычитаю одно из другого (из куба цилиндр) - получается поверхность внутри, надо посчитать ее площадь. Копирую лицо поверхности, получаю примитив "Surface". Выделяю - ничего не пишет кроме количества линий, образовавших поверхность.
Command: (entget(car(entsel)))
Select object: ((-1 . <Entity name: 7efaf2a8>) (0 . "SURFACE") (330 . <Entity
name: 7efaad18>) (5 . "C52D") (100 . "AcDbEntity") (67 . 0) (410 . "Model") (8
. "0") (100 . "AcDbModelerGeometry") (70 . 1) (1 . "mnmoo lg m mi ")
(1 . "ni ^*+0;:,4 ^*+0\\^[ nh ^LR nmqoqnqgmo QK o ") (1 . "n
fqfffffffffffffffj:rooh n:rono ") (1 . ">,27:>;:- {rn rn _nn mnmqoqnqgmo |") (1
. "=0;& {m rn {rn {l {rn {rn |") (1 . "-:9@)+r:&:r>++-6= {rn rn {rn {rn {n {k
{j |") (1 . "3*2/ {i rn {rn {rn {h {n |") (1 . ":&:@-:961:2:1+ {rn rn _j 8-6;
n _l +-6 n _k ,*-9 o _l >;5 o _k 8->; o _f /0,+<7:<4 o _k ,+03 oqhj _k 1+03 lo
_k ;,63 o _g 93>+1:,, o _h /6'>-:> o _k 72>' o _i 8-6;>- o _j 28-6; looo _j
*8-6; o _j )8-6; o _no :1;@96:3;, |") (1 . "):-+:'@+:2/3>+: {rn rn l o n g |")
(1 . "-:9@)+r:&:r>++-6= {rn rn {rn {rn {l {k {j |") (1 . ",7:33 {g rn {rn {rn
{rn {f {rn {l |") (1 . "-:9@)+r:&:r>++-6= {rn rn {rn {rn {h {k {j |") (1 .
"9><: {no rn {rn {rn {nn {h {rn {nm -:):-,:; ;0*=3: 0*+ |") (1 .
"92:,7r:&:r>++-6= {rn rn {nl {rn {f |") (1 . "300/ {rn rn {rn {rn {nk {f |") (1
. "<01:r,*-9><: {rn rn {rn kggjiqgnokmioloimg kfgkiqojnmljihnkn o o n o joo o o
n V V o n joo 90-(>-; V V V V |") (1 . "-:9@)+r:&:r>++-6= {rn rn {rn {no {f {k
{j |") (1 . "<0:;8: {rn rn {rn {nj {ni {rn {nh -:):-,:; {nn {rn |") (1 .
"<0:;8: {rn rn {rn {ng {nk {rn {nf -:):-,:; {nn {rn |") (1 . "<0:;8: {rn rn {rn
{nk {ng {rn {mo -:):-,:; {nn {rn |") (1 . ":;8: {mn rn {rn {mm o {ml nooo {nk
{mk 90-(>-; _j 4169: |") (1 . "<0:;8: {rn rn {rn {ni {nj {rn {mj -:):-,:; {nn
{rn |") (1 . ":;8: {mi rn {rn {mh o {mm lqnknjfmijljgfhfln {nj {mg 90-(>-; _h
*1410(1 |") (1 . ":;8: {mf rn {rn {ml rlqnknjfmijljgfhfln {lo o {ni {ln 90-(>-;
_h *1410(1 |") (1 . "/+36,+r:&:r>++-6= {rn rn {rn {rn {nh |") (1 . "):-+:' {rn
rn {rn {nh o {lm |") (1 . "):-+:' {rn rn {rn {nh n {ll |") (1 . ",+->687+r<*-):
{rn rn {rn kgljiqgnokmioloimg jogkiqojnmljihnkn o o rn o V V |") (1 . ":;8: {lk
rn {rn {lo o {mh nooo {ng {lj 90-(>-; _j 4169: |") (1 . "/+36,+r:&:r>++-6= {rn
rn {rn {rn {nf |") (1 . "):-+:' {rn rn {rn {nf o {li |") (1 . ":336/,:r<*-):
{rn rn {rn kggjiqgnokmioloimg jogkiqojnmljihnkn o ro rn o joo o o n V V |") (1
. "/+36,+r:&:r>++-6= {rn rn {rn {rn {mo |") (1 . "):-+:' {rn rn {rn {mj o {lh
|") (1 . ":336/,:r<*-): {rn rn {rn kggjiqgnokmioloimg kfgkiqojnmljihnkn o ro n
ro joo o o n V V |") (1 . "/061+ {rn rn {rn kgljiqgnokmioloimg
jogkiqojnmljihnkn o |") (1 . "/061+ {rn rn {rn kgljiqgnokmioloimg
kfgkiqojnmljihnkn o |") (1 . "/+36,+r:&:r>++-6= {rn rn {rn {rn {mj |") (1 .
",+->687+r<*-): {rn rn {rn kfljiqgnokmioloimg kfgkiqojnmljihnkn o o n o V V |")
(1 . "/061+ {rn rn {rn kfljiqgnokmioloimg jogkiqojnmljihnkn o |") (1 . "/061+
{rn rn {rn kfljiqgnokmioloimg kfgkiqojnmljihnkn o |") (100 . "AcDbSurface") (71
. 6) (72 . 6))