This Client Server article is republished in its entirety from 2002 for reference purposes.
By Mario Langlais, Technical Support Analyst - Applications Group, Bentley Canada Office 09 September 2002
Once known as Filters, an enhanced function called Color Masks appears in Bentley Descartes V8.
Basically, a Color Mask "masks out" specific colors. These colors can then be included or excluded from editing operations.
Color Masks have the following properties:
Figure 1: The Color Mask tool box
The Color Mask tool box contains 3 tools:
The color mask functionality has been made for MicroStation Descartes especially for 24-bit files. This feature allows us to specify which colors we want MicroStation Descartes to work on without modifying the others.
When one or more colors are set in a specified mask, all those colors in all images in the list will be considered when modified. This means that all the images in all views containing a specific RGB color will see the modifications applied on this RGB color.
Figure 2: The screen displayed before the blue was assigned to a mask
Figure 3: The screen displayed after the blue color is selected and highlighted As you can see in Figure 2, there are two different images. The blue color (representing the water) will be assigned to the "test" mask on the Colormap.iTIFF image. Once colors are assigned to a mask, there is the "highlight" tool that highlights in red all the colors assigned to the specified mask. As you can see in Figure 3, all the blue is highlighted in red. Also, as you can see, the blue is highlighted in all images, since this is the same RGB value.
As mentioned in the section above, more than one color can be set in a mask and these colors are "valid" for all the images displayed in all views. However, the sub-mask feature allows you to extract one or more colors from an existing mask for a specific image.
Figure 4: The screen displayed after the blue color is assigned to the sub-mask (as if it would have been removed from the mask) especially for the Color_Sub_Mask.iTIFF image As you can see in Figure 4, the blue is no longer highlighted on the Color_Sub_Mask.iTIFF image since it has been assigned to the "Test_Colormap_Sub_Mask.iTIFF" sub-mask for the Color_Sub_Mask.iTIFF image.
Previously, using Filters reduced the performance of MicroStation Descartes. Now, Color Masks have been optimized to make sure that whether or not you use a mask, the performance will remain the same.
The Color Mask and Sub-mask features are very useful when the time comes for you to either paint or erase data on one or more images. The only thing you have to do is set specific colors to a mask, activate this mask in the corresponding tool (Paint or Erase), then go ahead.
As you can see in Figure 5, the masks are very useful for painting. In the example below, the blue was assigned to the mask. So, when painting, only the blue was painted brown inside the block. All other colors stayed as they were.Figure 5
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