HOOPS Stream File Exporter

This export converter saves out the database to the HOOPS Stream File (.hsf) file format. The HOOPS Stream File (HSF) file format allows highly compressed files containing 3D data and bitmap images to be streamed over Internet connections of any bandwidth.

Online Scene Demos (HSF Files Exported by PolyTrans). Click any image

Related references

• Okino's HSF export converter press release [PDF Format]
  
  
• Tech Soft America's HSF gallery (www.hoops3d.com)

Important WEB Sites and Links Related to HSF File Viewing

• HOOPS HSF File Viewer (stand-alone Microsoft Windows viewer)
  
  
• HOOPS 3D Stream Control Download. ActiveX control to view HSF files in a WEB page.
  
  
• HOOPS Streaming File Gallery. Example of HSF files exported from CAD programs.

Advantages of Publishing to the HSF Web Streaming File Format

• No charge for displaying the HSF files on your WEB site. Some other WEB streaming file formats require broadcast license fees or fees to be paid for the publishing package. Okino Computer Graphics has paid a licensing fee upfront to TechSoft America on behalf of our customers.
  
  
• Free HSF viewer control for WEB browsers. Available for Windows, UNIX and Linux platforms.
  
  
• No WEB server configuration required. HSF streaming and viewing is a client-only solution, eliminating the need to endure the considerable IT burden of server-side configuration and maintenance. Users wishing to implement real time collaborative viewing or view-dependent streaming should refer to the HOOPS Net Server.
  
  
• Multiple levels of data compression: vertex, normals, polygon and file-level.
  
  
• Level of Detail support. Streams simpler models first, then successively more complex models.

An Overview of the HSF File Format

The HOOPS Stream File (HSF) format is a robust, customizable and highly compressed 2D/3D visualization format specifically tailored to the needs of displaying 3D model and scene data. Through its rapid widespread adoption and open, published nature, HSF is fast becoming a ubiquitous medium for applications to share visual data and for end users to publish and store their visual data.

What types of data is HSF appropriate for?

The HSF format is appropriate for visualization at all phases of the design - manufacture - commerce process chain including CAD/CAM/CAE and related downstream applications all of the way through to e-commerce.

What types of applications can use the HSF format?

HSF is useful for applications in the domains of design, analysis, digital mock-up, machining, view & mark-up, and e-commerce. HSF allows for the same visualization format to be used through all phases of the "art-to-part" process and all of the way through to point-of sale. This flexibility is critical given the trend toward "mass customization" where supplier and customer involvement is occurring further and further up the design process chain and, as such, the line where "e-commerce" begins continues to blur. What this trend reveals is that there should not be a separate format for visualization during the design, analysis and manufacturing phases and another at the point of e-commerce. There is no longer a firm wall between those domains and customers continue to require more sophisticated information about the product. HSF will handle the detailed needs of engineering as well as the lighter weights required for viewing at the point of purchase or during product marketing.

Publishing and Compression Options

This panel controls how the exported 3D data will be compressed into a smaller form to allow faster WEB streaming and viewing. It also provides controls over the final previewing of the exported HSF file with a WEB browser.

Publishing and Previewing

Output HTML file with embedded HSF viewer

Enabling this option creates an HTML page with the selected HSF file embedded. These HTML pages can then be posted to a web site as live 3D data. The HTML page also has an embedded HOOPS 3D Stream Control which will stream the HSF from either a local disk or a web site. The embedded object will, behind the scenes, download and install the HOOPS 3D Stream Control if it is not already installed on the machine reading the web page. This means that you simply need to put the HTML and HSF file on a Web site and any user of Microsoft Internet Explorer can view the model over the web by simply pointing their browser to the page's URL.

Preview in WEB browser when done

Enabling this option will cause your default WEB browser to be invoked to display the HTML page published with the above enabled option.

Compression Related Options

This HSF exporter provides lossless LZ compression of the overall entire file and sophisticated geometry-specific compression.  For example, the vertices, normals and vertex connectivity information of the exported mesh data as well as any Level-of-Detail LOD representations of the geometry are written out using compression techniques. Vertices and user-specified normals are written out with a compact, low resolution format rather than with the original floating-point representation. A variety of compression options can be set in order to balance the reduction in file size vs. the potential increase in export time. 

Enable LZ compression on entire file

This enables global compression on the entire file using the "zlib" lossless compression algorithm. It should always be enabled since zlib compression is fairly efficient and fast.

Enable vertex normal compression

Vertex normals are attributes of each mesh polygon that defines the overall curvature and resulting rendered smoothness of the object. They can consume a sizeable amount of steaming bandwidth and thus compression is desirable for them. Enabling this option will cause a degraded series of vertex normals to be streamed in the file. Selecting a lower number from the "Vertex normal bit depth compression" drop-down box will cause the HSF file to become smaller but at the expense of lower quality and imprecise vertex normals. Compressed vertex normals will cause faceting artifacts in areas of the model which are highly curved. If the model is not smooth or highly curved to start with then you could use a lower number of bits and still achieve good visual results. The default is 10 bits (which will provide some level of compression) while 24 bits will provide the best results in terms of quality but not compression.

Enable vertex coordinates compression

This compression technique involves encoding the locations of mesh vertices, providing reduction in file size in exchange for loss of coordinate precision and slightly lower visual quality.  The degradation in visual quality is highly dependent on the topology of the mesh, as well as how the normals information is being exported.  

Enable polygon connectivity compression

This compresses mesh geometry connectivity information.  This compression technique can provide compelling reductions in files sizes for datasets that contain many mesh primitives, but can also be a computationally intensive algorithm depending on the size of individual meshes.  You will need to decide for yourself whether the reduced file size is worth the extra computation time.  

Level of Detail (LOD) Generation

A very important aspect of streaming 3D files across network connections is the time taken to download and display an initial view of the 3D scene to the viewer. For larger models this time can be considerable. To compensate for this long download time "Level of Details" (LODs) can be used. LODs are lower resolution, smaller versions of the mesh models which stream down and display first before the final full resolution mesh arrives. The default exporter options will cause 2 smaller LOD models to be created first in the HSF file before the full resolution model is embedded.

Number of 'Levels of Details' (0 or more):

This determines how many LOD models will be created for the HSF file. 0 will create none. The default is 2.

Decimation amount

This slider determines how much each successive LOD model will be reduced in size. By default this value is 75%. Thus, the first model will be reduced to 75% of the full resolution mesh. The second model will be reduced to (75% x 75% = 56%). The LODs will stream in reverse order, such that the 56% compressed model comes first, the 75% model second and the non-decimated model last.

Decimation algorithm: Fast or Better

This determines which of the mesh decimation algorithms will be used: either the faster (but less appeasing) or better (slow but better more appeasing).

Enables Panel

This panel controls the output of specific geometric mesh attributes, lights, cameras, hierarchy, materials and texture definitions.

Mesh Data Export Options

The basic primitive used to define 3D models in the HSF file are "polygon meshes". The following are attributes associated with the output of the mesh data.

Output vertex normals

If this checkbox is checkmarked then vertex normals will be exported along with the mesh geometry. Vertex normals are used to specify where an object is to appear smooth and where it is to appear faceted (rough).

Output u,v texture map coordinates

If this checkbox is checkmarked then (u,v) vertex texture coordinates will be exported along with the mesh geometry. Uv texture coordinates are used to define how a bitmap texture image is to drape over and around a mesh model.

Want convex polygons only

Checkmark this checkbox to cause non-convex (concave) polygons to become triangulated. An example of a concave polygon is a "star shape".

Want quadrilateral polygons only

Checkmark this checkbox to cause 5 or more sided polygons to become triangulated.

Want triangles only

Checkmark this checkbox to cause 4 or more sided polygons to become triangulated.

Output Cameras

If this checkbox is checkmarked then the currently active will be output to the HSF file as the initial camera view.

Output Lights

If this checkbox is checkmarked then parameters associated with a light definition will be output, including those parameters for ambient, point, spot and directional light sources.

Light brightness Multiplier, #

The HOOPS streaming toolkit will try to internally balance the lighting of the scene depending on how many lights there are. A side effect of this automatic effect is that scenes may appear too dark when display. You can enter a light intensity "multiplier" value into this type-in box. Entering 2.0 will output the light intensities double their normal values while a value of 0.5 will output the light intensities at half their normal values.

Output materials ('surface' definitions)

If this checkbox is checkmarked then the following material attributes will be exported:

• Diffuse surface color.
• Specular highlight color.
• Face opacity.
• Phong highlight size.
• Reflection coefficient.
• And optionally the first diffuse texture map.

Enable and Embed Texture Images

If this checkbox is enabled then the first diffuse texture map assigned to the material will have its bitmap image read from disk and embedded directly inside the HSF file. This will require that the "uv texture coordinates" mesh option be enabled as well.

Texture Filtering Method:

This specifies the default texture filtering method for the destination HSF file viewer. When a texture image is blown up much larger or much smaller than its normal dimensions then "texture aliasing" artifacts can appear on the viewed model. To compensate for these aliasing artifacts the viewer program can perform "texture filtering". Multiple methods exist for the HSF exporter. "MIPmaps" and "Summed Area Tables" are common methods.