manual extension ge autocad

1

AUTODESK LABS

WHITE PAPER

The Google Earth™ Publishing Extension for AutoCAD 2008 Products (Disclaimer: Remember that this is all early beta software; really cool technology, but it’s unsupported, use at your own risk, etc. In other words, don’t use these tools on mission critical projects! Lastly, we make no guarantee that these products/features will ever be commercially available.)

0BOverview

This AutoCAD 2008 add-on application is useful in publishing and viewing your DWG-based data and 3D models within Google Earth™.

This publishing tool is designed to specifically meet the needs of Architects, Designers, and Engineers using Autodesk products. Using the easy-to-use, wizard-driven interface, you can publish your 3D models directly from AutoCAD into Google Earth.

From the planning process all the way through to public approval, everyone involved in your project can now view and navigate your projects in the context of the rich, interactive Google Earth environment. Benefits include:

• Deliver high-impact presentations at planning board meetings or public hearings

• Streamline the preliminary project planning process

• Share conceptual plans with your clients as they develop

• Connect everyone involved in your project from the planning stage through to public approval

See the help file for detailed information on how to publish Autodesk DWG data directly into Google Earth. Information on using this application can be found in the AeccDWGToGE.chm help file available with this product.

You can obtain a copy of Google Earth™ here: Hhttp://earth.google.com/ H . Please review your Google Earth license agreement for usage rights. Under their current license agreement, Google Earth Pro is the only product currently supported for image capture.

You will need version 4.1 or later of Google Earth for this product to work.

1BApplicable Products

• AutoCAD 2008

• AutoCAD Architectural 2008

• AutoCAD Civil 3D 2008

• AutoCAD Map 3D 2008

THE GOOGLE EARTH™ PUBLISHING EXTENSION FOR AUTOCAD 2008 PRODUCTS

2

Importing a Google Earth image into AutoCAD

Prior to publishing your 3D model into Google Earth, you should know the position of where the model will be placed on the earth's surface. The simplest method to achieve this is to first import a Google Earth view into AutoCAD.

You can import the current Google Earth view into AutoCAD as a raster image. The image entity may be used as a back drop for design or, more importantly, as a means to georeference the position of your DWG model.

Definition: Georeferencing is the process of associating the position of your DWG model with a particular location on the earth's surface, along with orienting the DWG model to a particular direction relative to north.

The primary use of this command is to bring an image into AutoCAD, and adjust the position of the image relative to your model such that the DWG model will lie in the proper position on the earth's surface.

Complete the following steps:

1. Start Google Earth, and zoom to the location on the earth's surface that you want to capture the image

2. Be sure you are looking straight down at the earth's surface (that is, the view does not have any tilt.)

3. Also, for best results, zoom in close enough to capture enough detail of the earth's surface in the area of interest

4. Lastly, keep the Google Earth application maximized. Do not minimize or collapse the Google Earth application.

5. Here’s what your display might look like (if you’re looking down on our HQ in San Rafael, CA):

Figure 2: Google Earth view of San Rafael, CA

Now you are ready to bring this image of the Google Earth view into AutoCAD.


3

1. Start AutoCAD, and select the button on the Google Earth toolbar (or, type “IMPORTGEIMAGE” at the AutoCAD Command Line.)

2. After a brief period, a rectangle representing the border of the image will be attached to the AutoCAD graphics cursor.

3. Next, you be prompted for the image location in the drawing:

a. If Civil 3D or Map 3D is in use, and a map projection is defined in the drawing, you’ll be provided with an option to a) use the map projection to automatically position the image in the drawing, or b) manually specify the desired location along with a rotation angle to orient the image as desired

b. If Civil 3D or Map 3D is not in used, or either product is being used but a map projection is not defined, you’ll only be prompted to manually position the image to the desired location, and then specify a rotation angle to orient the image as desired.

4. The image will be black and white – a current limitation imposed by Google Earth.

Your display should look similar to this figure:

Figure 3: San Rafael satellite image within AutoCAD


4

The following items may be of help:

• Once placed, you may use AutoCAD's 'move' and 'rotate' commands to further refine the position of the image relative to your model. Do not adjust the position of your DWG model. Rather, adjust the position of the image relative to your DWG model.

• The dimensions of the image in the drawing are defined by the extent of longitude and latitude the image covers in Google Earth, and a transformation of those extents using the insertion scale units of your DWG (AutoCAD INSUNITS system variable – set using the AutoCAD DDUNITS command).

• The image displayed in the drawing is an AcDbRasterImage, and is stored in the same directory as the DWG file. The first three letters of the image file name will be the same as the first three letters of the DWG file, and the image extension will be JPG.

• The image entity contains x-data stored with it that contains information about where on the earth's surface the image covers.

• The image brought into AutoCAD will only be black and white, even though the image in Google Earth is in color. There is no way to change this.


5

Publishing 3D DWG Models to Google Earth

To publish 3D DWG data to Google Earth, use the button on the AutoCAD Google Earth toolbar, or type PUBLISHKML at the AutoCAD command line.

Once the PUBLISHKML command is selected a set of dialog boxes in the form of a wizard is presented. Follow the directions given on each step of the wizard to publish the data.

Use the “Collect Data from Imported Google Earth Image” button on the third dialog, (called Geo-Reference) to pick your Earth position.

There are detailed tooltips for each item on the dialog boxes. Use the information in the tooltips to understand the effect each control has.

The following items are related to publishing DWG data to Google Earth:

• DWG model data is grouped under the Model folder in the Places pane.

• Grouped entities in the DWG are grouped in common folders under the Model folder within the Google Earth Places pane.

• Cameras and camera paths are grouped in Cameras and Paths folders in the Places pane.

• Colors of published entities in Google Earth are matched closely to AutoCAD colors.

• Only model space data may be published to Google Earth.

• If the Google Earth publishing extension is being used with Civil 3D 2008 or Map 3D 2008 and a map projection is defined, the default behavior is to automatically use the map projection formulae to convert from drawing coordinates to Google Earth latitude and longitude coordinates. You can optionally manually define the AutoCAD to Google Earth coordinate transformation on the Geo-Reference page of the publishing wizard, but a more accurate conversion is possible if the automatic map projection transformation is used (if one is available.)

When there are materials attached to model space entities in AutoCAD, you can publish the materials with the entities by toggling on the 'Publish Materials' options on the 'Items' dialog box page in the publishing tool. When materials are published, the following items should be noted:

• If time span information has been attached to AutoCAD entities, it is not published to Google Earth when materials are published.

• Grouped entities in the DWG are not grouped in common folders under the Model folder within the Google Earth Places pane.

• Toggles under the Model folder in the Places pane for individual entities published to Google Earth are not available.


6

When materials are not published from AutoCAD to Google Earth, the following items should be noted:

• If time span information has been attached to AutoCAD entities, it is published to Google Earth when materials are published.

• Grouped entities in the DWG are grouped in common folders under the Model folder within the Google Earth Places pane.

• Toggles under the Model folder in the Places pane for individual entities published to Google Earth are available.

• When the ‘Published Entity Information’ option on the ‘Items’ page of the publishing wizard is toggle on, certain textual information about some of the published entities will be published to Google Earth. These textual name/value pairs, or meta-data, are viewable in a pop-up window in Google Earth by selecting the individual entity in the ‘Places’ pane of Google Earth. The entity meta-data published varies from product-to-product, and is available when the publishing tool is used with AutoCAD Architecture 2008, AutoCAD Civil 3D 2008, and AutoCAD Map 3D 2008.

The follow figures detail the flow of the PUBLISHKML wizard:

Figure 4: Labeling your model for presentation in Google Earth

7

Figure 5: Select which objects to publish, enable text, materials, and ADT or C3D object properties

Figure 6: Locate your model on planet Earth with (left) and without (right) a map projection

Figure 7: Tools for offsetting your model

8

Figure 8: Save your model into a format Google Earth can read

Figure 9: Once saved, click on View to open Google Earth


9

2BDrape a greyscale Google Earth image onto a 3D mesh in AutoCAD

You can import the elevation data for the current Google Earth view into AutoCAD as a mesh.

A new material is also created in the current drawing file using the Google Earth view captured as a grayscale image. The new material is assigned to the newly created mesh.

With the Realistic visual style for an AutoCAD view port turned on, the image will appear as if it is draped on the newly created mesh.

Prior to using this command you should complete the following steps:

1. Start Google Earth, and zoom to the location on the earth's surface that you want to import the elevation data from.

2. Be sure you are looking straight down at the earth's surface (that is, the view does not have any tilt.)

3. Also, for best results, zoom in close enough to capture enough detail of the earth's surface in the area of interest

4. Lastly, and this is important, keep the Google Earth application maximized. Do not minimize or collapse the Google Earth application.

Figure 10: Google Earth satellite image

Now you are ready to bring a mesh of the Google Earth terrain into AutoCAD.


10

1. Start AutoCAD, and select the button on the Google Earth toolbar (or, type 'ImportGEMesh' at the AutoCAD Command Line.)

2. After a brief period, a mesh representing the terrain data will be attached to the AutoCAD graphics cursor.

3. Next, you be prompted for the image location in the drawing:

a. If Civil 3D or Map 3D is in use, and a map projection is defined in the drawing, you’ll be provided with an option to a) use the map projection to automatically position the image in the drawing, or b) manually specify the desired location along with a rotation angle to orient the image as desired

b. If Civil 3D or Map 3D is not in used, or either product is being used but a map projection is not defined, you’ll only be prompted to manually position the image to the desired location, and then specify a rotation angle to orient the image as desired.

4. In order to view the image draped onto the mesh, select “Realistic” from the list of Visual Styles located on the 3D Modeling Dashboard:

Figure 11: AutoCAD 3D Modeling Dashboard


11

Figure 12: Google Earth image draped onto an AutoCAD Mesh

The following items may be of help:

• Once placed, you may use AutoCAD's 'move' and 'rotate' commands to further refine the position of the mesh relative to your model. Do not adjust the position of your DWG model. Rather, adjust the position of the mesh relative to your DWG model.

• The dimensions of the mesh in the drawing are defined by the extent of longitude and latitude the mesh covers in Google Earth, and a transformation of those extents to the linear units of your DWG.

• The mesh displayed in the drawing is an AcDbPolygonMesh, and is of type simple mesh.

• The mesh size is fixed at 32 rows by 32 columns.

• The image captured from the Google Earth view is saved in the same folder as the drawing file, and has the same three-letter prefix as the first three letters in the drawing file name.

• The material created in the drawing is named using the first three letters of the drawing file, followed by several random numbers.

• The image captured from the Google Earth view will always be grayscale. There is no way to change this using this command, but see the steps below to drape a color image onto the mesh.


12

Drape a color Google Earth image onto a 3D mesh in AutoCAD

You can also import the elevation data for the current Google Earth view into AutoCAD as a color mesh.

To drape a color image onto an AutoCAD mesh, follow these steps:

1. Orient the Google Earth view to the area of interest, and ensure you are looking straight down at the earth's surface.

2. Import the mesh into AutoCAD using the steps outlined above.

3. From within Google Earth, save an image of the current Google Earth view using Google Earth's 'File > Save > Save Image' command.

4. Save the Google Earth image in the same folder as your drawing file.

5. From within AutoCAD, create a new material using the 'MATERIALS' command.

Figure 13: AutoCAD Materials Dialog Box

6. Attach the saved image to the new material's diffuse map.

7. Under the "Material Scaling and Tiling" options, set:


13

o Scale units = Fit to Gizmo o U Tile = None (scale = 1.0) o V Tile = None (scale = 1.0)

8. Under the "Material Offset and Preview" options, set: o U Offset = 0.0 o V Offset = 0.0 o Rotation = 0.0

9. Attach the new material to the imported mesh.

10. Using the 'MATERIALMAP' command, select the "Planar" option, and apply it to the mesh.

11. Finally, change to the realistic 3D view mode using the 'SHADEMODE' command, and the color image should appear draped on the mesh:

Figure 14: Google Earth color image draped onto an AutoCAD Mesh


14

3BAttach Time Span (or 4D) Information to your model

Google Earth provides the ability to conditionally display published model data based on start and end times attached to each piece of model data. These start and end times are referred to as an entity's time span. This is a useful tool where you need to present development progress over a period of time.

Attaching time span information to AutoCAD entities is entirely optional. If you decide to attach start and end times to AutoCAD model space entities then, when the model is published to Google Earth, you can use the time tool within that application to control the display of the model data:

Figure 15: Google Earth Date/Time control

Prior to attaching time information, you should analyze your model and decide on the best technique to associate time with the various entities. This will vary from model to model. For example, for a structural framing model, you might associate one time span with the first floor columns, a second time span with the second floor beams, and so on. Using this technique would allow you to animate the upward construction of the building framing.

In Figure 16, let’s assume we want to show the progress of the development of the parking garage (in dark blue) over the course of two months.

Figure 16: Sample building with Parking Garage


15

To attach time span data, we use the button on the toolbar, or type 'GETime' at the AutoCAD Command Line.

Next, you’ll want to select object(s) and then assign a start/end time to each. This will determine when the objects selected will appear and then disappear when you adjust the Google Earth Date/Time control (see Figure 15 above.)

Here’s what you’ll see in AutoCAD:

Figure 16: AutoCAD dialog for date/time assignments

We can assign start/finish times to each level of the parking garage. When finished, we can publish this model data to Google Earth using the button on the AutoCAD Google Earth toolbar (or type “PUBLISHKML” at the AutoCAD command line.)

Once publication is complete, you can switch over to Google Earth to view the results. In the following figure, we can adjust the Google Earth Date/Time slider to watch our parking garage come together from beginning to end. This screen capture shows the beginning stages of our development:


16

Figure 17: Google Earth playback

The following items are related to attaching time information to DWG data and publishing it to Google Earth:

• If a start time is not attached to an entity, then the entity will display starting at the beginning of the time slider tool in Google Earth.

• Similarly, if an end time is not attached to an entity, then the entity will display from the start time through to the end of the slider bar.

• An entity without any time span information attached to it will always be displayed in Google Earth.

• Time information associated with AutoCAD model space entities is attached to those entities using X-Data.

• You can not include time span information in published models that you have also chosen to publish materials. Either time information can be published or material information can be published, but not both.

• If you hover over an entity with time span data attached, a tooltip with the start and end times will be displayed.

• Existing time span data attached to an entity can be updated by rerunning the GETime command on the entity.


17

4BCommand Reference Command Name Description

IMPORTGEIMAGE Brings current Google Earth view into AutoCAD as raster image. Use this command to georeference your DWG model data to correct position on earth’s surface.

IMPORTGEMESH Brings elevation data in current Google Earth view into AutoCAD as a mesh.

PUBLISHKML Exports your 3D DWG model space entities to an external file for use within Google Earth.

GETIME Attaches time span information to AutoCAD entities which will be honored by the time tool available in Google Earth.


18

5BVersion History Command Name Description

June, 2006 Initial release on labs site Compatible with AutoCAD 2007 and related verticals

April, 2007 Release version compatible with AutoCAD 2008, AutoCAD Architecture 2008, and AutoCAD Civil 3D 2008 Add GETime and ImportGEMesh commands Add support for publishing materials

October, 2008 Add support for AutoCAD Map 3D 2008 Add support for map projects when AutoCAD Civil 3D 2008 or AutoCAD Map 3D 2008 is detected Added tool tips for showing time span data attached using GETime command Add diagnostic dialog that is displayed when a communication interface to Google Earth cannot be established from AutoCAD. Add check to ensure at least version 4.0 of Google Earth is being used Blocks can now be published without exploding Numerous other minor bug fixes.

Autodesk [and other products] are either registered trademarks or trademarks of Autodesk, Inc., in the USA and/or other countries. All other brand names, product names, or trademarks belong to their respective holders. Autodesk reserves the right to alter product offerings and specifications at any time without notice, and is not responsible for typographical or graphical errors that may appear in this document.

manual extension ge autocad

Documents