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WebOOGL Formats

Before placing WebOOGL files on your HTTP server, be sure to add the following line to your server's mime.types file:

    object/x-oogl   oogl off list tlist grp quad mesh inst bez vect

Standard OOGL Formats

WebOOGL includes all of OOGL's standard geometry formats, as defined in the OOGL Manual (for an introduction, see the OOGL Tutorial). Particularly noteworthy for WebOOGL are the facilities in OOGL for symbolic references to objects, as in

    { : handle_name }
This allows "standard" objects to be defined and then reused later in separately downloaded files.

Inlining Remote Objects

An inlined object in OOGL is specified using the keyword "<", followed by the location of the data file. In WebOOGL, the location is allowed to be any World-Wide Web Universal Resource Locator (URL). Some examples:

    { < http://geometry.org/surface.mesh }

    { < gopher://gopher.hole/00/buckteeth.oogl }
Note that the inlining capability isn't a general textual "include" mechanism; a complete OOGL object must appear in the referenced data.

Currently, relative URLs are only supported for the case of local files. So for now you should always give the complete URL address of any inlined object.

Making Hyperlinks to Remote Resources

A hyperlink is an invisible WebOOGL object which holds a URL. It can be specified using the keyword ">", followed by the URL. The URL is then optionally followed by keyword/value pairs describing other link attributes, as defined in HTML; the most important are the link relationship attributes rel and rev. URLs containing OOGL metacharacters (such as '#') must be enclosed in double quotes.

A hyperlink is associated with other objects through inclusion in a LIST object. Objects in sublists will be associated with the same hyperlink, unless these sublists contain their own hyperlinks. Here is an example which links an inlined object to its HTML description:

    { < http://geometry.org/weird-thing.oogl }
    { > http://geometry.org/explanation.html }

To follow a hyperlink, the user selects one of the associated objects (right mouse click, in Geomview). The meaning of "following" a link depends on the relationship between the current object and the one referenced by the link. By default, the new object is presented to the user in a fresh view, typically replacing the current visible world if it again consists of WebOOGL data.

In contrast, specifying the Embed relationship indicates to the viewer that the referenced object should be inlined into the existing 3D world, in the coordinate system of the link. The WorldEmbed relationship is similar, except that it uses world coordinates. For example, to create an "icon" that will expand to a more complex object when selected, the following construction can be used:

    { < http://www.server/icon.oogl }
    { > http://www.server/expanded.oogl  rel WorldEmbed }
(Note: the only relationship implemented in the current WebOOGL system is WorldEmbed.)

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Comments to: webmaster@geom.umn.edu
Created: Apr 24 1996 --- Last modified: Apr 24 1996