Importing Contours
into 3D VIZ
©2000-2 Central Visual Information Systems, Inc.  Reproduction of this document is prohibited.

Why we need Contour Data in VIZ

You may want the site information to create animations and/or still frame exterior shots of your building or civil project. Often you will have access to contour data from the surveyor/civil engineer. This Method & Practice should make this easy from you.

There is more that you can do with contour information in VIZ. Typically one of the parts of any architectural or civil visualization project is showing site location information. You can accomplish this in a variety of graphic applications. VIZ has some advantages over just using a simple picture. You can do “Parachute Drop” animations, “Fly-in”s, etc.  These are simple to do in VIZ.

About the Authors
Tench Tilghman is the founder and Chief Technical Officer of CVIS, Inc. He has spent more than 25 years working in the AEC industry as a contractor, project manager, architect, CAD manager, trainer, and computer-aided-design consultant.
Portions of this document were produced and edited by multiple members of CVIS Technical Services staff without whose knowledge and expertise this document would be impossible to produce.
Special recognition to the Clients of CVIS and their staffs who aided in the validation and review of the contents.

Contact Us  support@cvis.com            Visit Us  www.cvis.com
Phone 1-800-511-8020     Fax 1-800-511-8021     4630 West Jacquelyn Suite #108  Fresno, CA 93722
©2001 Central Visual Information Systems, Inc.  Reproduction of this document is prohibited.

Introduction

We cover how to bring in contours from a civil engineering or survey drawing and create a terrain object. There are some handy features in the object. You could use the terrain objects as your scene’s platform. This may be necessary if you have drastic changes of slope in your animation. Another sneaky use of terrain objects is to employ them as distant objects in your scene. This is one way to create important background features and topographic landmarks for your animation. Terrain objects are also great for site fly-ins. Everyone it appears loves the “crash from space”.


Linking to A DWG File

We need some data to build a new type of VIZ object…A Terrain. We are going to use DWG File Linking to do this in this exercise. We are going to grab contours (2D polyline with elevations) from a civil engineering drawing as a source of data from a surface.

1.             Open VIZ

2.             Set up your viewports as shown on the right

3.             Pick the Utilities tab on the Command Panel
You can get to the Asset Browser here.
Also this is where you find Camera Match

Behind the More button there are even more goodies including a polygon counter. This is good for judging and managing the complexity of your models. Think of this as a better way to judge the size of your model.

These are good things to explore here later.

4.             Click of the File Link Manager button
The File Link Manager is also available in the Insert menu
The File Link Manager dialogue box allows you to Attach a DWG file, reach into it and link to objects in the DWG file.

5.             Click on the Attach button

6.             In the File dialogue box navigate to
and select the CONTOURS.DWG.
Here we are using an example drawing. You can use your own.

7.             Click on Open to Attach the DWG

8.             OOPS! We get a warning message!
VIZ is coordinate system aware. This is often IMPORTANT when you work with civil engineers, surveyors and mapping folks.
This warning message is telling you that the DWG has an assigned coordinate system and that your current max session does not.
You probably want them to agree if you are Linking to the DWG file.
For our purposes we don’t care because we are just going to Bind (extract) the contours anyway.
If you do care, you can set the coordinate system for VIZ in Tools>>Options.

9.             Pick on the NO button
We do NOT care.

10.         VIZ is different from AutoCAD. It has a different file structure and the objects are different too. It is pretty cool the most of the translation between a DWG and a max file works so well and can be dynamic.
We do have to tell VIZ what to do with the DWG objects.
Pick on the Attach tab
VIZ has default values and saves them for you each time you use the File Link Manager

11.         Set the Attach values as shown here
Pick One Object from the Combine By list box
       This will make all of the polylines a single VIZ object
        THE ONLY THING WE WANT are polylines with elevation from our AutoCAD drawing.
Uncheck the Preserve Access to Individual Objects
       We are not going to need to edit the polylines in VIZ
Check the Hide Origin Point Helper
        This special Helper object comes in handy sometimes, but now it is just something we’ll never use.
Uncheck the Rescale to Match Units
        We are not worrying about matching scale now
        If you DO care leave it checked.

12.         Pick on the Geometry tab

13.         Set the values as shown here
Uncheck ALL of the values
We are bringing in line objects only so these parameters designed for meshes and 3D objects do NOT apply.

14.         Pick on the DWG Linking tab

15.         Set the values as shown here
Check Convert Drawing Layers to Design Layers
       Handy to keep things the same in VIZ and AutoCAD
       Actually NOT too important for this process
Uncheck Create Instances of Blocks
       NO blocks are coming in
Uncheck Resolve External Reference dwgs
       No Xrefs to deal with
Check Skip Hatches and Points
       No Hatches or Points either

16.         Pick on the Exclude Objects by Layer button
We don’t want everything in the DWG-only the contour polylines that are all on one layer.

17.         In the Select Layers box you can select what DWG layers you will attach (Link) to.
You almost never want everything in the DWG

18.         Pick on the Invert button
This unselects ALL of the Layers
This is almost always a good place to start

19.         After you’ve picked the Invert button there will be little “X”s in front of all the layer names

Find the CONT-MNL layer in the list
This example came from a typical Land Desktop drawing
You want a layer with ONLY polylines at elevation

Pick on the “X” in front of the name
The only objects we want from the DWG file are on this layer

Things shown look like the picture to the right.

20.         Pick OK to confirm your choice of Layers

21.         Back in the File Link Setting dialogue box
Pick OK to start the File Linking process

VIZ putters along creating the links and creating the objects in VIZ based on your parameters.
The process can take a while if you are Linking a large number and/or complex drawing objects.
VIZ gives you a running progress report down in the Status Line area.

22.         When things are done you end up back in the File Link Manager dialogue box.
We are going to do one more thing here.

We are going to Bind the objects permanently into our max file.
We’re doing this for performance reasons in VIZ.
VIZ will have ONLY ONE file’s worth of data to cope with after this process.
The Bind process will destroy the dynamic VIZ and AutoCAD links we just created.
We will have actually done a DWG Import but with some better control of what we are actually getting.

23.         Select the DWG file in the list of files
VIZ will show you that the file is Linked to a VIZBlock object
This is one way to find where Linked objects come from.

24.         Pick the Bind button
VIZ warns you that you are breaking the Links to the DWG file

25.         Pick Yes

26.         Here is a Top view of the contours now inside VIZ as a single object.

You may have NO VISIBLE objects in your drawing!
Where are the contours?

27.         Click on the Zoom Extents All icon
No Contours

28.         Type H and select the object by name
It’s called VIZBLOCK## unless you renamed it

29.         Click on the Zoom to Extents Selected icon  
Still no objects
What is going on?
You know the contours are there but you cannot see them.

When you link an AutoCAD drawing VIZ places a Helper object in your scene.
We hid the origin pointer in the import parameters, but VIZ ALWAYS makes it. The helper holds the File Link attachment information.
The Helper is down at 0,0,0
Your contours are probably way out in space in State Plane or whatever coordinate system they were created in. Effectively the contours are reduced to a single microdot on your screen.
How do we fix this? We’re simply going to move them en mass.

30.         Select the contour object by Name

31.         Pick on the Move icon

32.         Right Click on the Move icon to bring up the Transform box
Look where the contour object is located
                                                                                    
It is way out in space. The limits of our scene are really really BIG. 
No wonder we can’t see them.

33.         Set the X,Y, and Z values in the Absolute World value boxes all to “0”

34.         Click on the Zoom Extents Selected icon
There are the contours
                                                                                                          

Creating The Terrain

Next we are going to create a surface from the 2D polylines. To do this VIZ has a special object called a Terrain Object. VIZ uses a simplified version of the Surface generator found in the Land Desktop product. Architectural Desktop uses another version to generate roofs!

1.             Since the contours were the last thing created the VIZBlock0# object should be Selected. If it isn’t, Select it

2.             Pick on the Create tab on the Command Panel

3.             Pick on the Geometry  icon

4.             Pick AEC Extended from the list of objects to Create

5.             Pick on the Terrain button
VIZ will grind away and compute the surface
You can control the surface and how it is represented in VIZ

6.             Here’s a view of the Terrain in a Top view viewed in Wireframe mode

7.             Terrains have a lot of parameters
Notice that like Boolean objects they are an attached object.
We’ll leave this Terrian01 object we created as a Reference

Pick Operand: Adds splines to the terrain object. You might do this if you didn't select all the objects before generating the terrain object, or if some objects in the imported data weren't included in the terrain object. You can also use this option to add existing splines in the current design to the terrain object.

When you click Pick Operand, the copy method you designate determines how the operands are used. When Move is the method, the original contour data is moved from the scene and into the operands of the new terrain object. Copy, Reference and Instance retain the original contour data in the scene and create copies, references or instances of the contour data as operands in the terrain object.

8.             You can display the Terrian in 3 ways
Form group

Graded Surface: Creates a graded surface of the mesh over the contours.

Graded Solid: Creates a graded surface with skirts around the sides and a bottom surface. This represents a solid that is visible from every direction.

Layered Solid: Creates a "wedding cake" or laminated solid similar to cardboard architectural models.

Stitch Border: When on, suppresses the creation of new triangles around the edges of terrain objects when edge conditions are defined by splines that are not closed. Most terrain forms display more reasonably when this is turned off.

Retriangulate: The basic Terrain algorithm tends to flatten or notch contours when they turn sharply upon themselves. A typical situation when this may happen is when a narrow creek bed is described with contours- the resulting form my look more like a series of cascades at each elevational contour rather than a smoothly descending ravine. When Retriangulate is checked, a somewhat slower algorithm is used that follows contour lines more closely. This may be particularly evident in the Layered Solid display mode. For additional precision, try using Retriangulate in conjunction with horizontal interpolation.

9.             You can Display the Terrian with or without contours

10.         Just like Booleans you can Update the Terrain Manually
This is very handy if you are going to make a lot of changes to the parameters since otherwise the Terrain is recomputed with every change
Set the Update property to Manual for now!

11.         You can add and subtract how much of the contour data is used to compute the Terrian.
We’ll leave these alone for now, but recognize that you probably do not need as many data points as you think you do in most Terrians.

Elevating the Terrain

You can Color a Terrian without adding a material to it!

1.             Pan down until you find the Color By Elevation rollout

2.             Expand the section

Maximum Elev.: Displays the maximum elevation in the Z axis of the terrain object.

Minimum Elev.: Displays the minimum elevation in the Z axis of the terrain object.

VIZ derives these values from the contour data.

Reference Elev.: This is the reference elevation, or datum, that VIZ uses as a guide for assigning colors to zones of elevation.

3.             Enter a Reference Elevation value of 300

4.             Click on the Create Defaults button
VIZ generates a default set of color Zones based on the elevations of the contours. VIZ lists the elevation at the bottom of each zone, referenced to the reference elevation. VIZ applies the color of the zone at the base elevation. Whether the colors blend between zones depends on your choice of the Blend to Color Above or Solid to Top of Zone option.

Here are the ranges VIZ builds based on our contours.

If you enter a Reference Elevation value no greater than the minimum elevation in the object, VIZ divides the range between the reference and minimum elevations into five color zones: dark green, light green, yellow, purple, and light gray.
That’s what we just did!

If you enter a value between the minimum and maximum elevations, VIZ creates six color zones. Two zones (dark blue and light blue) are used for elevations below the reference elevation. These are considered to be under water. One zone (dark yellow) is used for a narrow range around the reference elevation. Three zones (dark green, light green, light yellow) are used for elevations above the reference elevation.

If you enter a value at or above the maximum elevation, VIZ divides the range between the minimum and reference elevations into three zones (dark blue, medium blue, light blue).

5.             Select each of the elevations in the list

6.             Set the Base Elev value as shown to the right

7.             Check the Blend to Color Above radio button

8.             Pick on the Modify Zone  button to make your changes to the Zone.

9.             Pick the next number in the list and repeat the process for all five Zones

Base Elev: This is the base elevation of a zone to which you assign color.

Base Color: Click the color swatch to change the color of the zone.

Blend to Color Above: Blends the color of the current zone to the color of the zone above it.

Solid to Top of Zone: Makes a solid color at the top of the zone without blending to the color of the zone above it.

The items here assign colors to elevation zones. If you make changes in here, they do NOT affect the terrain object until you click the Modify Zone or Add Zone button.

Modify Zone:  Modifies selected options of a zone.

Add Zone:  Adds values and selected options for a new zone.

Delete Zone:  Deletes a selected zone.

10.         Pan back up to the Update section

11.         Pick on the Update button to commit your changes

12.         Now you can Set the Update property back by checking the Always radio button

13.         Set the Top view view mode to Smooth + Highlights
Your view should look like this

14.         Save the max file

 

About the Authors
Tench Tilghman is the founder and Chief Technical Officer of CVIS, Inc. He has spent more than 25 years working in the AEC industry as a contractor, project manager, architect, CAD manager, trainer, and computer-aided-design consultant.
Portions of this document were produced and edited by multiple members of CVIS Technical Services staff without whose knowledge and expertise this document would be impossible to produce.
Special recognition to the Clients of CVIS and their staffs who aided in the validation and review of the contents.

Contact Us  support@cvis.com            Visit Us  cvis.com
Phone 1-800-511-8020     Fax 1-800-511-8021     4630 West Jacquelyn Suite #108  Fresno, CA 93722
©2000-2 Central Visual Information Systems, Inc.  Reproduction of this document is prohibited.
Late updated on 3/26/2002 9:04 AM