Shaded graphics

The shaded graphics mode renders the model as a collection of solid objects with lighting, shading, perspective and hidden line removal.

Figure: Shaded graphics

Using the shaded graphics mode

To a large extent there is no extra work required to build a model for the shaded graphics mode. You can build a model (or take an existing model) in wire frame mode and simply change to shaded graphics mode to see a high quality shaded rendering of your model. There are, in addition, a number of things you can do to improve your experience with the shaded graphics mode as described below.

Translucency

The sea surface and seabed are drawn as textured surfaces. If there are objects on the other side of these surfaces then they can be obscured. The degree of translucency of the sea surface and seabed can be adjusted to avoid this.

Importing 3D models

Objects like lines are straightforward to draw. OrcaFlex uses the line type outer contact diameter to determine the thickness of each segment of the line.

Other objects, such as vessels, present more difficulties. OrcaFlex will, by default, draw a solid, filled-in shape based on the wire frame data of the object. While this can often be sufficient, you may prefer something more elaborate, in which case you can import a more detailed 3D model, e.g. the turret-moored FPSO above. You can import 3D models for 6D buoys, wings and shapes as well as for vessels.

We provide with OrcaFlex a very basic collection of generic models which you are free to use. These are an FPSO, a turret-moored FPSO, an installation vessel, a semisub and a subsea template. For information on generating and importing 3D models specific to your project please refer to importing 3D models.

Viewer position

Because the isometric wire frame view is perspective-free, it does not have a viewer position associated with it. Shaded graphics mode, however, does use perspective and so, as well as the view centre, requires in addition the concept of the viewer position. In OrcaFlex we define the viewer position to be in a line in the view direction (defined by the view azimuth and view elevation) at a distance of view size $\times$ 1.5 from the view centre. It is possible to rotate the view around both the view centre and around the viewer position.

Video export

As with wire frame views, OrcaFlex can export video files of replays in shaded views. When producing videos it is very important to use compression, otherwise the video file size quickly becomes unreasonably large. The software that performs this compression is called a codec.

For wire frame replays OrcaFlex uses a Windows codec called run-length encoding. This codec is not, however, suitable for shaded replays; in fact, there is no suitable built-in codec in Windows. Consequently, if you wish to export shaded-mode videos, you may need to install an appropriate codec yourself. We recommend using an MPEG-4 codec, many of which are available. In our experience the freely available XVID codec performs very well.

The XVID codec can be downloaded from Xvid. Once installed we recommend that you make the following minor configuration changes to the XVID encoder:

The XVID encoder settings can be found in Start Menu | Programs | Xvid | Configure Encoder.

In order to export videos from 64 bit OrcaFlex, you must have a 64 bit codec installed. The latest versions of the XVID codec install both 32 and 64 bit versions. However, if you installed an older version of XVID you might only have the 32 bit version of the codec installed: in this case, you will need to install the latest version for 64 bit compatibility.

If you wish to install and use a different codec, you must define its properties on the preferences form. Packages containing a number of different video codecs are available on the internet, but you should be aware that these are usually the decoders only (for viewing video): they do not generally contain the encoder part necessary to create video, so cannot be used by OrcaFlex to export video.

Hardware requirements

The shaded graphics mode requires a DirectX 9 compatible graphics card. In our experience the most important factor to consider when choosing a card to work with shaded graphics is the amount of memory. We would recommend using a card with 256MB or more. Your computer's graphics settings should specify a colour mode of 16 bits (65536 colours) or better.

Notes: If your machine's graphics capabilities are insufficient then the shaded graphics mode may fail to function properly or indeed fail to function at all. For example, low quality, blocky images usually indicate a graphics card with insufficient memory. This problem can also manifest itself by failure to draw the sky, which instead appears plain white.
For best results you should centre your model close to the global origin. The move selected objects facility can help you do this.