Exporting VRML

Exporting Models To VRML

What Is VRML ?

VRML is the web-standard language for describing virtual objects and worlds. VRML may be included in web pages and viewed using VRML-enabled browsers. In this way VRML allows 3D interactive graphics to be included on a web page.

Do I Need VRML ?

Models may be viewed and refined using Real2Virtual Viewer. This is fine for developing a model , but for publication on a web page you must export the model into VRML format. A VRML model can be published directly to the Web, or viewed off-line using a VRML enabled browser.

Alternatively VRML models may be converted to IBM HotMedia format, which enables them to be viewed using a standard browser without any plug-in. This is how the models are presented in this document.

How do I Enable VRML On My browser?

You will need to download a VRML "plug-in" for your browser. This is simply a program that will add itself to your browser to add VRML functionality.

If you are using Internet Explorer or Netscape Navigator the you can use the free Cortona VRML client (download now)

Blaxxun also supply a free VRML Add-in for Internet Explorer . This is available from blaxxun.com.

Visit www.web3d.org/vrml/vrml.htm to find out about more plug-ins for your browser, and to check for new releases.

How do I Export VRML ?

Select the "Tools->Export VRML" menu option, the following dialog is shown,

Modeller can output VRML in VRML1.0 format, or the newer VRML2.0/VRML97 format. Select the desired version using the radio buttons in the VRML Version group.

If you are exporting VRML for use with IBM HotMedia then select the Hotmedia Compatible checkbox. Note that in this case VRML1.0 is disabled as HotMedia cannot load this format.

By default the VRML model will be placed so that the viewer initially sees the Front of the object. However, you may specify a starting position and orientation of your choosing.

If you do not wish the object to be placed at the origin of the VRML coordinate system, enter the desired starting coordinates in the Position of Model group. The position of the model is described in units of meters, in the VRML Coordinate System shown in the dialog's diagram.

In addition you may use the Clockwise Rotation of Model group to specify a rotation to be applied to the model before exporting. The rotation is specified as a set of three rotations about the VRML Coordinate System. The default values of (x=0,y=0,z=0) is equivalent to no rotation of the model.

To change the size of the model use the Scale of Model group, select the Re-scale model checkbox and enter the diameter of a sphere in meters. The model will be re-sized to fit inside this sphere.

Note : very large or very small models look incorrect in some viewers . If your model looks wrong in a VRML viewer this may be the problem, rescaling the model will fix this.

Finally if your model has surface texture then you may use the JPEG Quality group to specify the quality of the JPEG images that will store this texture. High quality images take up more space and will take longer to download, but will look better than low quality images.

Change any values as desired and then select Export. You will then be prompted for a file name. Alternatively, you may select OK, in which case the settings are saved as part of the project for future use

When a model is exported, Modeller creates a .wrl file (VRML file) and in addition a number of texture images in JPEG format (if the model has texture). The JPEG images are stored in the same directory as the .wrl file. These files together form a model.

Compression of VRML Models

VRML may be compressed using GZip to produce much smaller files, for use in applications where model size is important - for use on Web-pages for example. GZipping a .wrl (VRML) file will create a compressed VRML file with a .wrz extension. VRML-enabled browsers should automatically recognise either .wrl or .wrz files, but we recommend that you keep the .wrl extension even for compressed files, as not all web-servers support the .wrz extension properly.

Note that the JPEG texture images are already compressed, and there is no need to compress these further.

Publishing a Model On The Web

Modeller generates a Web-Page for you when it exports a model. This page will have the same name as the model, but will have a .htm extension. For example the horse model when exported creates a horse.htm file, which it stores with the other exported files. To publish the model on the web simply upload the .htm, .jpg and .wrl files which make up the model to your web-site. Then link a page to the .htm

You may prefer to embed the model in one of your own pages. To do this you use the HTML EMBED command anywhere in the body of your page, as follows,

<EMBED src="MyModel.wrl" width="500" height="300">

You can make width and height any values which fit for your page, the model will always be displayed with the correct aspect-ratio so you need not worry about having the correct ratio for these values.

IBM HotMedia Support

You can publish VRML models on Web pages without requiring that the user of the page has a VRML enabled browser. This is how the models in this document are published.

To do this use IBM HotMedia to publish the model. This method of publishing models has the following advantages,

Using HotMedia means that the viewer of your web page need not have a VRML viewer installed. The user can see the model without having to first download and install software components.
HotMedia compresses VRML files into much smaller files. The model will be transfered faster than the equivalent VRML.
Hotmedia takes the collection of files which make up a VRML model and creates a single file (.mvr).
Hotmedia allows a VRML to be mixed with other types of media such as background images and sound to give a multimedia experience.

Modeller can tailor it's VRML to give better compatibility with HotMedia. If you are exporting VRML for use with HotMedia, enable the HotMedia Compatability option. To do this select the Project->Settings menu option then select the Build tab. On this page check the Ensure VRML is HotMedia Compatible checkbox.

Alternatively you can set this option from the export dialog described above.