3.6. Reference: The 3DSOM Pro Settings Window

The 3DSOM Pro Settings Window is shown in Figure 3.6.1. It can be opened by pressing the Change settings... button or choosing File > Settings... menu item.

All settings are saved with and loaded from the 3DSOM Project file except for the "Automatically scroll canvas when painting" option. To return to the default values for all settings, select the Defaults button. Press the OK button to keep any changes you have made and close the window. If you press the Cancel button any changes you have made will be discarded.

Most of the settings can be adjusted when doing individual processing steps, however it can be useful to set up default values so that operations such as Processing > Make All menu item can run without interruption. Most settings are also saved with the 3DSOM Project, so will always be the defaults the next time you load the project.

"Mask Generation Settings"

These settings affect the automatic mask generation used in the Mask Wizard (described in the Masking the images section) and initial behaviour for mask slider for the Regenerate mask button and Shrink-wrap Mask button.

The "Background detection threshold" controls how much of the image is treated as background when it is masked. A higher value produces more mask. Adjust this value if you find too much or too little of your images is being masked.

When the "Use colour normalisation" option (visible on the Edit Masks toolbar as the "Shadows" option) is selected the auto-masking tries to compensate for shadows falling on the backdrop. If you have your lighting set-up well it is best to deselect this option at first.

When the "Use sub-sampled images" option is enabled, 3DSOM Pro will create lower resolution versions of very high resolution images to speed up the masking and texturing processes. If you wish to create the highest possible quality model deselect this option.

"Wireframe Generation Properties"

These settings affect the wireframe generation used in the Surface Wizard (described in the Building the wireframe model section).

The "Silhouette decimation threshold" is used to remove unwanted detail in the silhouettes before generating the surface. This will avoid too many unwanted triangles being created and speed up the process. If you want to capture every last detail in your silhouettes, reduce this value.

The "Default number of triangles" determines the initial number of triangles used to display the model when it is created. The number of triangles can also be interactively changed after the geometry has been generated (see The View Model Window section).

The "Maximum surface error" is an alternative advanced way of determining how many triangles will be displayed after wireframe generation has completed which is useful when you are scanning many objects. If you leave it at its default value of zero, then it will be ignored. It is described in more detail in the box below.

Controlling surface accuracy It is sometimes difficult to know how many triangles will be needed to model a particular object accurately. 3DSOM Pro can try to set the number of triangles for you so that the object is approximated to a certain accuracy. You can control how accurate you want the mesh by adjusting the "Maximum surface error" - you should be able to apply the same number across all your projects to get the same level of detail. The smaller this number, the more triangles you will get. The "Default number of triangles" is still used to limit the number of triangles, so if you want more than the default, you will need to set this higher as well. Again, you can always change the number of triangles later without having to regenerate the wireframe.

When the "Automatically align high-angle cameras" option is selected during wireframe generation, 3DSOM Pro will automatically try to adjust any images taken from high-angles to compensate for poor calibration. You should use this option only if you suspect there is a problem with the geometry due to the alignment of high-angle cameras, often visible as the model becoming too "thin" when these images are "included".

"Texture Generation Properties"

These settings affect the texture generation in the Texture Wizard (described in the Adding the surface texture section).

The "Texture map size" sets the size in pixels of the texture map. The texture map is always square and the size determines the tradeoff between the detail in the texture and the amount of storage required for the texture map. Generally values such as 512 or 1024 pixels tend to be adequate for most uses. The maximum allowed value will depend on the available physical memory. For systems with 0.5Gb of memory the maximum is around 2048 pixels square. For systems with 2Gb of memory or more the maximum will be up to 4096 pixels square. The actual model displayed may use a downsampled texture map depending on the graphics card resources.

When the "Tone correct textures" flag is enabled, 3DSOM Pro will try to compensate for variations in exposure between the images which would otherwise cause the surface texture to have unwanted variations in intensity. If you are using controlled lighting conditions or are experiencing unwanted colour shifts in the textures you may wish to turn this option off.

When the "Texture boosting" option is enabled, 3DSOM Pro automatically picks a set of up to 6 key views and uses these to add detail to the texture map. Otherwise, 3DSOM Pro will attempt to blend together information from all the images, which can result in unwanted blurring or shadowing of details, particularly if there is any slight mis-registration, inaccuracies in the geometry, or movement of the object during photography.

"Export Properties"

These settings affect the default values in the Export Window (described in the Exporting the finished model section).

The "Texture quality" reduces the size of the texture map as saved on disk by changing the compression at the expense of reducing the texture quality - this is a value between 1 (lowest quality) and 100 (highest quality).

The "Geometry quality" determines how the geometry data is compressed and is a value between 1 (lowest quality, smallest size) and 100 (highest quality, largest size). Values below 50 are not recommended for normal use.

"Workspace Properties"

These settings control how the masks and model are displayed in the Edit Masks Window and View Model Window.

Various colours are used in the interface and can be altered to suit the images and object being modelled. Altering the displayed mask colour can be very helpful during mask editing. Similarly, when aligning images, changing the wireframe or solid colours can make it easier to see what is going on. Clicking on any of the colours opens a standard colour selection dialog.

The "Automatically scroll canvas when painting" option can be disabled to stop the Edit Masks Window scrolling when painting near the edge of the window. With certain graphics cards or alternative mouse hardware such as a tablet, this feature may make painting difficult.

"Mat Scale"

The "Mat Scale" setting allows you to input the size of the calibration mat so that you can import and export correctly scaled 3D models (in mm units). Simply measure and enter the length of the "mat unit" on the printed mat.

Once the correct mat scale has been enterd, you can import 3D models in 3DS or STL formats (in mm units) and they will be correctly scaled in relation to the input photos.

3DSOM Pro also uses this setting to correctly scale the 3D models when exporting the final models. 3D models will be exported in mm units. If you export a 3DS model and re-import you should make sure the "Mat Scale" setting has not been changed between export and reimport.