The extract contours functionality allows the user to extract the contours generated from the full resolution terrain data contains in a STM (i.e. : Scalable Terrain Model). The extracted contours will be added to the .dgn as MicroStation vector elements.
Here is a short video showing the extraction of contours for a region of the STM.
Usability tip : As the video shows, the region of the STM from which the contours has to be extracted cannot be too large. So using a more precise region (e.g. : road corridor, terrain not rectangular) will optimize the chance of being able to extract the contours for the desired region in one pass.
The contours extracted automatically inherit the properties of the contours generated for the STM. So for setting the appearance (e.g. : smoothing, text labeling, color, etc...) of the contours to extract you must change the appearance of the STM contours in the Element Information dialog.
Usability Tip : The contours for the STM must be turned on in order to extract the contours from the STM.
Usability Tip : It is possible that the extracted contours differ from the contours displayed for the STM. This is because the contours displayed for the STM is generated from the resolution of the STM currently used, which is often lower than the full resolution terrain data contained in the STM.