Before even starting to think about creating a 3D scene from AutoCAD data, a separate simplified drawing must be created taking elements from a design drawing. The drawing below is a good example of an AutoCAD landscape design drawing. However, this is not suitable for import into MAX/VIZ as it contains hatches, text, image references, detailed blocks etc that MAX/VIZ will not use
Just those drawing elements needed for creating good surfaces, edges and objects are copied and pasted into a new AutoCAD drawing and quickly optimised for export to MAX/VIZ
NOTE: Ref: 'Key Fundamentals / Infrastructure and Landscape Modelling' for guidance on how to use good drawing methods in AutoCAD
TIP: Keep elements in a design drawing on layers ready for easy copy and pasting to an optimised drawing for 3D to minimise any redrawing. A well organised CAD project should involve as little redrawing for 3D as possible
In order to follow this tutorial, you may want to use the supplied files. Please read the sample data instructions before downloading.
Unzip the training files to the relevant folders, putting the dwg files in the Drawings folder and the scene files in the Scenes folder
NOTE: It is advisable to use the Key 3D Start Template as the MAX/VIZ Start Template. This contains many quick-start features and settings. Select the Key 3D Template and press MAX/VIZ Start Template to do this. It will then appear under the MAX/VIZ Start Template group box and will open up automatically when MAX/VIZ starts
Whenever creating a scene from a design production drawing always separate the data to be used for 3D work by copying into a new drawing and naming this 'buffer' drawing specifically 'for 3D'. This helps deal with issues such as optimising framework lines, simplifying blocks and moving the data nearer to 0,0. It also removes most of the drawing data that will not be used by MAX/VIZ and allows for a straight forward and comprehensive transition. Below, is an explanation of how to do this, but for the purposes of this tutorial a buffer drawing has been created
TIP: Use a template drawing with predefined layers and blocks to speed up this process
NOTE: The 'G_Framework' layer is used to help create surface boundaries using the Boundary command
Optimising framework lines involves inserting, deleting or moving vertices to give the appropriate amount of vertices on the lines and improving design elements such as the smoothness of curves that would benefit the 3D graphics greatly. This optimisation will, in turn, optimise the boundary lines created from the framework lines in the next stage. To optimise the framework lines they are imported into MAX/VIZ and the powerfull spline sub-object tools used before exporting back to AutoCAD to create the surface boundaries
NOTE: A feel for the correct level of detail on the lines at this stage can overcome potential problems when creating a terrain from a copy of the lines at a later stage. Lack of faces or too many faces on parts of the terrain can be avoided
NOTE: This exercise outlines quite extensive editing of the framework lines to give you a wider experience of the MAX/VIZ sub-object editing tools. In practice, more would probably be done in AutoCAD to form curves around intersections and entrances before importing the lines into MAX/VIZ
TIP: Uncheck these layers and press Invert to speed up the process of selecting the layers to import
NOTE: In this instance vertices should be added. However, some imported lines may need vertices removing if there are too many. In general, use Corner type vertices whenever possible and adjust the level of detail to suit the proximity of final viewing
TIP: On longer sections where vertices need adding use the Divide tool in segment mode to quickly add uniform vertices
TIP: Be careful when selecting vertices and turning them to corner type. If you turn bezier type vertices to corner type on sections of the line that have not had vertices added then you will lose the intended geometry of the line (ie the line will not be 'anchored' with new vertices as intended). If this happens use Undo and re-select the line
The framework lines for the paths within the parkland have been created using arcs in AutoCAD. The vertices on these lines are translated into bezier type vertices when imported into MAX/VIZ and typically have few vertices on the lines. To optimise these lines and vertices for use in MAX/VIZ, the amount of vertices need increasing where needed, removing where not needed and the type changing to corner type vertices. Although the curves will then be made of straight segments (as with the road corners and due to using corner vertices), this method means that you have complete control over the level of detail required in the surface mesh. Plus, auto-generation of many faces as a result of using bezier type vertices on a boundary line when cutting out inner surfaces from larger surfaces later will be avoided
NOTE: Remember that the aim here is to get complete control over the amount of face detail on the final 3D surfaces. You need high detail around curves and within the more detailed design areas and less detail in areas of less detail design such as the middle of grassed areas and the context landform. The reason you are using MAX/VIZ to do this at this stage (before exporting back to AutoCAD) is because MAX/VIZ has more efficient tools to edit vertices on lines than AutoCAD
Firstly, change the System Unit Setup settings to millimeters:
Then export the framework lines to AutoCAD:
All boundaries for 3D surface creation must be drawn in AutoCAD as closed boundary polygons that have been created using accurate geometrical drawing techniques. This process has been aided by adding a framework layer that has been edited and optimised in MAX/VIZ. The Boundary command is now used in AutoCAD to create the surface boundaries and to make sure that all the boundaries are seamless
NOTE: Double lines delineating a kerb in the 2D plan are not imported into MAX/VIZ, just the seamless boundaries of one surface next to another. Kerbs are created entirely in MAX/VIZ by using the Key 3D Edging routines, involving the use of the Loft compound object. In MAX/VIZ the 3D kerb will extend over the 3D road surface which will be lowered about 150mm (as it is in real-world). Because the kerb will extend over the road it is the back of kerb line that is used for the road boundary
NOTE: A site boundary has been created on layer B_Site. This is used to create a site surface, thus separating the design surfaces from the context surface (which will be far less detailed)
NOTE: An advantage of creating surface boundaries using the Boundary command is that they do not contain 'intersecting vertices' (a common problem in 3D modelling work). Creating boundaries in this way also ensures that the polygons are completely closed. Closed boundaries are also useful in AutoCAD for hatching, obtaining area quantities and export to other 3rd party applications such as Corel Draw and Adobe Illustrator
Complicated 2D blocks should not be imported into MAX/VIZ if they are merely used as markers for 3D Objects or, as in this case, for replacing with 3D objects. Replacing blocks with much simpler blocks before importing into MAX/VIZ is straightforward in AutoCAD using the Block Editor. This exercise explains how this was done in the tutorial project drawings
NOTE: The Edit Block Definition dialog is a feature of AutoCAD 2007 plus. Replacing blocks in previous versions of AutoCAD entails using the Reference Edit dialog or simply 'redefining blocks'
TIP: Another option for replacing blocks can be found on the Express Menu/Blocks. Use Replace block with another block to quickly replace a block in the drawining with another
The AutoCAD drawing used for this tutorial is positioned close to zero on the X and Y axes. However, it is very common for land planning and architectural project drawings to be positioned far from 0,0 due to the use of Ordnance Survey georeferenced data. This can cause problems later on in the 3D project, when some modelling operations may fail and animated cameras may 'shake'
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