Luminaires - part 2 - 24 : particular requirements - luminaires with limited surface temperatures 燈具.第2 - 24部分:特殊要求.帶有限表面溫度的燈具
Luminaires . part 2 : particular requirements . section 24 : luminaires with limited surface temperatures 光源.第2部分:特殊要求.第24節(jié):限制表面溫度的光源
Luminaires - part 2 : particular requirements ; section 24 : luminaires with limited surface temperatures iec 60598 - 2 - 24 : 1997 , modified ; german version en 60598 - 2 - 24 : 1998 燈具.第2部分:特殊要求.第24節(jié):限制表面溫度的燈具
The problems include catmull - clark subdivision surfaces ca n ' t precisely represent standard conicoid except paraboloid , and it ca n ' t modify the shape of limited surfaces when the original control mesh be given 如: catmull - clark細(xì)分曲面無法精確表示除拋物面外的常規(guī)二次曲面;在給定初始控制網(wǎng)格的情況下,難以調(diào)整所生成曲面的形狀等。
When parameter t unequal to zero the limited surfaces are proved at least c1 continuous except at extraordinary points . moreover , we can use this subdivision algorithm as pretreatment for catmull - clark subdivision . secondly , an adjustable catmull - clark subdivision algorithm based on c - b - splines is proposed 文中對這族細(xì)分曲面的性質(zhì)進(jìn)行了較詳盡的分析,并證明了在參數(shù)t不等于零時這族曲面在非奇異點(diǎn)處至少具有c ~ 1連續(xù)。
The main innovation of our method is that we only need construct polygonal mesh possessing simple symmetric properties on both sides of control polygon edges of interpolated curves , and do n ' t need modify the subdivision rules near the interpolation curves during the process of subdivision . thus the subdivision rules are simple . the process is convergent and the limit surface is c everywhere except a finite number of points 該方法的主要創(chuàng)新思想是,在被插值曲線的控制多邊形兩側(cè)構(gòu)造具有簡單對稱性質(zhì)的多邊形網(wǎng)格,而在細(xì)分過程中,則無須修改被插值曲線附近的細(xì)分規(guī)則,兇此細(xì)分算法是簡單的,細(xì)分過程是收斂的,且最終的插值曲面除有限個點(diǎn)外是c ~ 2連續(xù)的。
However most subdivision schemes do n ' t take the limit surface ' s convergence to some user - definded position parameters into account . so subdivision surfaces are always applied in computer animation and artware shape design , not in reverse engineering in which the position - setting constrains are appended to the result surfaces , precision machine design and medical image reconstruction 然而由于大多數(shù)細(xì)分算法不考慮極限曲面收斂到用戶指定的某些位置參數(shù),細(xì)分曲面的應(yīng)用始終只能局限在計(jì)算機(jī)動畫和工藝品設(shè)計(jì),無法越雷池半步,應(yīng)用到對曲面有定位約束要求的反求工程中,參與精密機(jī)械設(shè)計(jì)與醫(yī)學(xué)圖象重建。