Start with a pencil and paper and imagine a layer cake on a plate!!!!
Draw five boxes one on top of each other. Each box represents a layer (Construct) of the cake (Model) The layers are not equal in thickness so the diagram is used to determine each thickness. Layer one is say 2 feet thick (Foundation/Footing) Layers two, three and four are equal thickness of say 10 feet (First floor/Second floor/Third floor). Layer five (Roof) may be iced later so if you think it will be 10 feet allow fifteen feet. (This will make sure your photo (Elevation) of the finished cake will not cut off the icing and candles.(roof covering and chimneys) The cream filling between the layers represent the datums of each floor.
Oops the bottom layer has slipped under the plate and you have noticed that it and the top layer are wider than the others when you look down on it. ( Plan or Top view).
NOW turn on the computer. Go to Project Navigator click Project tab enter your details at the top and then in Levels box below left click on the Edit Levels icon on right hand side. This brings up the levels dialogue box click on blue icon on top right to create new levels. Type in Foundation in name box. In Floor Elevation box (refer to your paper diagram and read off the calculated levels)enter MINUS two feet(-2). In the Floor to Floor Elevation box enter two feet ( NO minus) Make sure Auto –adjust Elevation box (bottom left) is ticked. Click on blue icon to create a new Level. Now type in First floor and the Floor Elevation box should automatically read 0. Type in ten feet in Floor to Floor Height box. Repeat process for each further layer (Second Floor, Third Floor, Roof) Remember to make roof height oversize.
Floor Elevation is relative to cake overall height while Floor to Floor Height is relative to height within cake layer
Set up your five Constructs as normal. Open First Floor Construct in Top View and decide whether to draw your external walls (set at ten feet high) or else a polyline outline of the walls. NOW start to draw from first point at 0,0,0, regardless of wall or polyline. Polyline is easier at this first principle level.and it can be converted to walls later.
Having created a polyline outline of plan of first floor check that it is definitely at 0 in Z coordinate by highlighting and looking at elevation box in geometry category of PROPERTIES palette if correct, copy to each of the other Constructs NOW. Your foundation/footing will be wider but at least you have the plan position of your walls and you can calculate how much wider the outside edge of footing will be and the same applies for your roof overhang. When you open up each Construct in turn it will have a polyline outline at level 0.
To go back to the cake analogy each Construct is a layer of the cake and within that layer all heights are relative to that layer. So if something is placed at MINUS one foot it will stick down one foot into the layer below when you assemble the cake (model)
The Model is the assembled cake and the Levels are the recipe to the chef to tell him to assemble the layers in a set height order. The foundation is negative because it slipped under the plate(0 level datum)
The Levels can be adjusted later if you change the recipe to six layers of cake and additional ingredients (constructs) can be added to represent say a floor slab as long as you tell chef (Project Navigator) what layer (Level) it is on. By starting the new Construct with the copy of the polyline from your first Construct you are establishing position relative to X and Y coordinates and Project Navigator will know from that information and the Level information where to place anything you draw (wherever you draw it) within the three- dimensional model
The polyline can be drawn on a non –plot layer or else deleted once some objects are inserted in the Construct and relative positions have been set.
Each Construct is a 3D world of its own but the Model is a collection of 3D worlds set on top of each other at heights determined by setting the Levels.
This may seen a silly analogy and very long winded but until you understand the fundamental principles of Project Navigator none of it makes sense and there are so many alien terms to familiarise with that it drives you round in circles. If you can imagine something simplistic it helps to put things in perspective. Most of the people who reply to questions on this forum are extremely clever and very steeped in ADT and have long forgotten that they once found it difficult to get started. Once you understand how it collects what seems disjointed information and puts it together to form the 3D model and then takes it apart again to print out flat printed plans you have the secrets of alchemy and can make your own gold.
Must go –all that talk of cake has made me hungry
TerryT