Re: STL-Color file format specification

From: Marcus Joppe (
Date: Tue Oct 23 2001 - 11:15:40 EEST


attached you will find a specification for the STL format to use colour
information which has been published to the rp-ml sometime ago.

Within the STL binary format each triangle is defined by a section of 50Byte.
The first 48Byte are used to describe the geometry information of the
triangle (triangle normal and points). The remaining 2Byte in the attribute
count are reserved for further information, but the interpretation of this
information is undefined within the "original" STL specification (should be
set to zero as default).

For every triangle the colour information is described in the attribute count
(16 bits).
bit 15 always 1 (to distinguish from normal stl files)
bit 10 to 14 intensity level for red (0 to 31)
bit 5 to 9 intensity level for green (0 to 31)
bit 0 to 4 intensity level for blue (0 to 31)
In this way there are 32768 different colours.

We are using this extension within our VisCAM RP software and we know that
others like TNO and BMT are using the colour extension in the same way. But
since there is no "official" standard for colour within the STL format yet,
others can use different extensions.

Best regards

---------------------------------------------------- Marcus Joppe Marcam Engineering GmbH Managing Director Fahrenheitstraße 1 D-28359 Bremen Tel.: +49 (0)421/2208-336 eMail: Fax: +49 (0)421/2208-337 ----------------------------------------------------

Dean Coe schrieb:

> Does anybody on the list know where I can find the technical spec for the > "color" STL file format? > Thanks to all for your anticipated help > > Dean Coe > Sanders Design International > > For more information about the rp-ml, see

For more information about the rp-ml, see

For more information about the rp-ml, see

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