Due to the complex nature of bridge modeling and the desire to increase the level of detail on bridge models generated using OpenBridge Modeler, several users have requested the ability to be able use the MicroStation tools to modify the bridge models generated in OBM. We are now introducing in OBM for the first time, the option to allow users to use modify bridge elements directly within OBM. Users can now apply several of the solid modification tools available under the modeling workflow and modify the native objects generated by OBM without having to drop the rules and intelligence. In prior releases of OBM this was only possible if the user dropped all OBM parametric rules and converted the entire bridge to a purely graphical representation of the bridge.

After users modify an object, if there is a change causing the rules to be re-evaluated and bridge updated, the user applied changes are still preserved. This is a great feature allowing for changes to the final model even after several solid operations are made.

Some typical examples of such modifications include clipping of top flanges of concrete girders due to skew, modeling of simple break backs at deck corners, adjusting the face of concrete barriers to cut normal at skew supports/ends, making weep/drainage holes in footings and backwalls, cuts to indicate staged construction, cuts in footing objects to avoid clashing with subsurface utilities etcetera.

Since these changes to the objects are done using MicroStation modification tools outside of the control of core OpenBridge control, the properties or the quantities do not reflect the changes made. This is a fine balance users must strike between the LOD on the model and loss of updated properties and quantities. Users must decide and implement appropriate workflows based on their needs on a project by project basis or stage of the project itself depending on what is driving the specific need at the point in time. Several publications recommend using multiple models, and it could be a valid approach here.

Some recommendations for best practices are to use a separate physical model with a higher LOD for the detailing and drawing production purpose. At this point only minor changes like cuts, holes, chamfers and fillets are recommended. Also these kind of modifications should be done at the final stage when no further major changes are expected on the model. Where possible, the native OBM modeling tools must be used, for example, if user wanted to shorten a specific pile, it is best done natively with OBM using the pile depth property. This will result in OBM storing the appropriate length of the pile, pile top and bottom elevations, quantity reports etcetera through the entire lifecycle of the model. Just cutting off a pile using the solid manipulation tools results in loss of accuracy of such information.

Research and development efforts in this area are continuing and some options to allow users to overwrite native OBM object properties may be provided in future releases.