Re: Texture mapping and STL conversions

From: Bert VandenBerg (
Date: Thu May 21 1998 - 00:56:13 EEST

Monica & Glenn Whiteside wrote:
> Dear rp-ml:
> I was reading an article this weekend in Machine Design (May 7, 1998
> issue, pp. 33-34) about IronCAD software from Visionary Design
> Systems, Santa Clara, CA which has some neat features. One of these
> features is called texture mapping which helps minimize model sizes by
> showing what would be data-intensive details, such as threads or
> screen meshes, as features that come from a library. The threads
> would be described in notes on the draft or 2D drawing without having
> a precisely detailed solid model in 3D space. I'm wondering how this
> texture mapping works (or doesn't work) with STL file conversion. Are
> the current STL converters able to deal with texture mapping? If not,
> what are the ways around this? Would you end up having to create the
> soild entity anyways?
> Just curious....

Think of texture as pieces of a 2D bitmap, stretched over a 3D (polygon)
model. Thus for the thread example, a "picture" of a thread is probably
stored in the texture map (usually a separate file), and stretched over
a model of a (smooth) cylinder. The human eye thinks it looks like a
threaded cylinder, at least until you zoom in close. To my knowledge
texture is not supported by STL. Rather you need a format such as
inventor (.iv), vrml (.wrl). These formats can support a 3D model of a
(polygonal) thread, or texture mapped cylinder. For fastening models,
one would probably like a STEP or CAD-level representation which stored
textured models.

(self promotion to follow):
The texturing approach is an effective way of reducing the quantity of
data required for hi-resolution display of museum artifacts (as acquired
by our colorScan, and converted to a 'textured' model by Innovmetric's

Bert van den Berg                   E-mail:
Hymarc Ltd.                 
35 Antares Drive                        Tel: (613) 727-1584
Ottawa, Ontario  K2E 8B1                Fax: (613) 727-0441

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