SketchUp Animation - "Spiral Staircase"

One great feature of SketchUp is how fly-through or fly-over or fly-by animation could be produced on the fly. And coupled with "section plane" function one has no problem producing cool construction sequence at all.

It's been a while since I last made any animation with SketchUp. I used the spiral staircase model I made, which I also shared on that page, throw in a few sections and scenes and here's the result:

This is not a real construction or assembly sequence by all means, I made this to brush up my rusty "section-planing" skill.

Like usual, the scenes are exported as 4000x2250pix PNGs and assembled in VirtualDub and encoded using x264 codec. VirtualDub can be found here, and x264vfw here.

Simple AutoLISP Code: Flip Dimension Text

This is a command I called D180, which function is rotating a dimension text by 180 degree.

(defun errD180 (msg)
(command)
(setq *error* localErrorD180)
(prompt "\nError. Program cancelled. ")
(princ)
)

(defun C:D180 (/ localErrorD180 dimProperty dimTxtRotationOld dimTxtRotationNew dimTxtRotationUpdate)
(setq localErrorD180 *error*)
(setq *error* errD180)
(setq dimProperty (entget (car (entsel "\nSelect dimension: "))))
(setq dimTxtRotationOld (cdr (assoc 51 dimProperty)))
(setq dimTxtRotationNew (+ dimTxtRotationOld (deg2rad 180)))
(setq dimTxtRotationUpdate (subst (cons 51 dimTxtRotationNew) (assoc 51 dimProperty) dimProperty))
(entmod dimTxtRotationUpdate)
(setq *error* localErrorD180)
(princ)
)
(defun deg2rad (d)
(* pi (/ d 180.0))
)

I must admit the codes are rather clumpy and crude. I've seen the same purpose achieved by lesser lines and much elegant codes, but that's beyond my programming skill. :-)