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You can control the accuracy of the image with various image computation parameters. The most important ones of these are the on-screen image resolution parameters. An experienced user may also find the parameters useful, to optimize the computation times and image quality.

The available options are:
- Start and last resolutions -
These two parameters define the drawing resolution for computing images on screen. They determine how large the macro pixels will be used to start the rendering, and how small they will be refined too.
A macro pixel is a ‘super’ pixel that is a multiple of the normal pixels. For example, a value of 8 would mean computing 8 ´ 8 pixel samples of the actual image then refining these to 4 then 2 then 1. Each refinement of the picture halves the value, thus, only powers of two (1, 2, 4, 8, 16,...) are allowed for the macro pixel sizes.
Last resolution value determines when the refinement stops. A value of zero leads to antialiasing the image in the last refinement.
- Antialiasing -
Antialiasing means that the picture is refined one step further than the single pixel size, to the so-called sub-pixel resolution. This results in a high-quality picture where the intensity variations between individual pixels have been smoothed out. The picture looks less ‘computer generated’.
The default is to compute four samples per pixel for antialiasing. This is enough for most purposes, but for very high quality images, you may try larger values. Small antialiasing values, on the other hand, make the computation faster. A value of zero means no antialiasing.
- Antialiasing tolerance -
This parameter affects where in the image antialiasing is applied. Antialiasing is not done for pixels whose intensity is already close enough to the neighboring pixels. If you only wish to have antialiasing where the intensity variations are noticeable, such as object silhouettes, choose a large tolerance value. This may save a lot of computation time.
- Cell capacity -
This parameter affects some optimizations regarding how objects are stored in ExTrace. You may only need to alter it when dealing with very, very large models. Setting a large cell capacity slows down the computation, but it helps with memory problems.
- Reflection rays -
The maximum number of individual ray bounces can be altered. The default value of five is more than enough for all practical purposes, but it may consume a lot of computation time in complex mirroring scenes.
The value of two is usually a sensible minimum choice. You will then see objects mirroring each other, and in the mirrored images one further level of mirroring.
- Shadows -
Determines whether shadows are computed or not. By default, they will, but with rendering glass objects shadows might not be required, and it could save a lot of computation time to switch the shadows off.
- ExTrace object updating -
When the objects, materials and textures are changed in Deskartes the information in ExTrace needs to be updated to. The options are
- Ask on material change - Using this option, only material and texture changes are updated into ExTrace, and the permission for each change is asked from the user separately.
- Ask on any object change - With this option, material and texture changes are updated into ExTrace without asking, but the system will also update any other object changes after asking for permission from the user.
- Automatic update / don't ask - With this option the system updates all object changes into ExTrace automatically, without any user interaction.