如何投影？

cwz206

请问，我画一个杯子，要在杯子外表面画5个波浪型曲线，每条曲线有6个波浪，应该怎样投影呢？[em12][em12]<img src="attachments/dvbbs/2003-11/20031114927816200.gif" border="0" onload="if(this.width>screen.width*0.7) {this.resized=true; this.width=screen.width*0.7; this.alt=\'Click here to open new window\nCTRL+Mouse wheel to zoom in/out\';}" onmouseover="if(this.width>screen.width*0.7) {this.resized=true; this.width=screen.width*0.7; this.style.cursor=\'hand\'; this.alt=\'Click here to open new window\nCTRL+Mouse wheel to zoom in/out\';}" onclick="if(!this.resized) {return true;} else {window.open(\'attachments/dvbbs/2003-11/20031114927816200.gif\');}" onmousewheel="return imgzoom(this);" alt="" />

cwz206

请指教。