[求助]如何求多个三维点组成的三角形面积累加？

yeekun

如何求多个三维点组成的三角形面积累加？

suntao008

你最好贴个图上来看看

yeekun

 [求助]如何求多个三维点组成的三角形面积累加?

yeekun

 [求助]如何求多个三维点组成的三角形面积累加?

ZZXXQQ

2. (DEFUN C:3PA () ;明经 ZZXXQQ
3. (SETQ PT1 (GETPOINT "\nFirst Point : "))
4. (SETQ PT2 (GETPOINT PT1 "\nSecond Point : "))
5. (SETQ PT3 (GETPOINT PT2 "\nThird Point : "))
6. (SETQ SAREA 0)
7. (WHILE (AND PT1 PT2 PT3)
8.   (SETQ SAREA (+ (AREA3 PT1 PT2 PT3) SAREA))
9.   (SETQ PT1 (GETPOINT "\nFirst Point : "))
10.   (SETQ PT2 (GETPOINT PT1 "\nSecond Point : "))
11.   (SETQ PT3 (GETPOINT PT2 "\nThird Point : "))
12. )
13. (PRINC SAREA)
14. (PRINC)
15. )
16. (DEFUN AREA3 (P1 P2 P3) ;;;三点求面积
17. (SETQ A (DISTANCE P1 P2)
18.        B (DISTANCE P2 P3)
19.        C (DISTANCE P3 P1)
20.        S (/ (+ A B C) 2))
21. (SQRT (* S (- S A) (- S B) (- S C)))
22. )

复制代码

ZZXXQQ

没有样图进行调试，所以只能编成人工选择的程序。
要不然就再画一个红色的三角形以视区别。

2. (DEFUN C:3PA () ;明经 ZZXXQQ
3. (SETQ PT1 (GETPOINT "\nFirst Point : "))
4. (SETQ PT2 (GETPOINT PT1 "\nSecond Point : "))
5. (SETQ PT3 (GETPOINT PT2 "\nThird Point : "))
6. (SETQ SAREA 0)
7. (COMMAND ".UNDO" "BE")
8. (COMMAND "COLOR" 1)
9. (WHILE (AND PT1 PT2 PT3)
10.   (SETQ SAREA (+ (AREA3 PT1 PT2 PT3) SAREA))
11.   (COMMAND "3DPOLY" PT1 PT2 PT3 "C")
12.   (SETQ PT1 (GETPOINT "\nFirst Point : "))
13.   (SETQ PT2 (GETPOINT PT1 "\nSecond Point : "))
14.   (SETQ PT3 (GETPOINT PT2 "\nThird Point : "))
15. )
16. (COMMAND ".UNDO" "E")
17. (PRINC SAREA)
18. (PRINC)
19. )
20. (DEFUN AREA3 (P1 P2 P3) ;;;三点求面积
21. (SETQ A (DISTANCE P1 P2)
22.        B (DISTANCE P2 P3)
23.        C (DISTANCE P3 P1)
24.        S (/ (+ A B C) 2))
25. (SQRT (* S (- S A) (- S B) (- S C)))
26. )

复制代码