Create terrain from DWG files

Importing contour lines

It is recommended that DWG files be adjusted using the Drawings Pretreatment Guide function in our CAD plugin prior to import.

Learn more about Drawings Pretreatment Guide.

Create terrain

The GIF below shows the process of creating terrain from DWG file:

Configure the DWG import dialog as shown below：

Note: Ensure the length unit matches the unit used in the DWG file.

Check terrain

Terrain generation typically takes less than one minute.

After create the terrain,user can activate the contour line layer and the CAD-import layer to inspect the fitness between the contour lines and the terrain.

If the alignment is unsatisfactory, increase the Number of elevation points used.

Generally, the number of terrain elevation points should not exceed 500,000, with a maximum value of 1,000,000. Increasing the number of elevation points improves terrain accuracy but may reduce the speed of subsequent operations. To strike a balance between computational speed and modeling accuracy, larger projects may consider adopting the following three methods:

Method 1: Set creation range

Use multiple closed polylines on a separate layer to define the terrain generation range, and create terrain only within these ranges.

Method 2: Set key areas

During terrain creation, you can designate the red‑line area as a key area.

Check Set Key Areas and select the corresponding layer (normally the red‑line area, which must be a closed polyline, multiple areas are supported).The terrain point density inside the key area will be higher than outside. The Key areas times can be configured in User Settings.

The picture as below is a topographic map of a massive 63 million ㎡, compare the effects of densification in key areas (with the Key areas times is 4, and the area within the dashed line represents the Key Areas):


No key areas	Key areas

Terrace topography

Representing terraces with contour lines

Version 1.6.1 and later have added a terrain generation algorithm optimized for terraces.

This algorithm is designed for topographic maps that represent terrace ridges with dense contour lines.

When using this algorithm, the software generates terrain based on contour lines, strictly limiting the crossing of contour lines. After generating the terrain, if there are still many triangular faces crossing ridges, it is necessary to increase the number of terrain elevation points in the "Create Terrain" interface and regenerate.

When using this algorithm, the software generates terrain based on contour lines while strictly preventing contours from crossing.If numerous triangular faces still cross ridges after terrain generation, increase the Number of elevation points used.

Only scarp lines and elevation points are available

In this case, there are no contour lines within the area, only scarp lines(terrace ridges) and elevation points.

In version 1.8.1 and later, support has been added for creating terraced terrain using scarp lines and elevation points with CAD plugins.

The specific steps include:

Step 1: Use the Convert DMTZ Terrace Lines to Contour Lines function in the CAD plugin,contour lines will be generated from scarp lines(terrace ridges) and elevation points and placed on the DMTZ_DGX layer.

The main principle is to generate two contour lines of different elevations on both sides of the scarp line to represent steep slopes.

Step 2: After creation, please check the purple lines.

These lines usually appear because the adjacent scarp lines lack valid elevation points in the corresponding direction. You may manually add elevation points and regenerate the contour lines.

Step 3: There are three scenarios for importing DWG files into SketchUp:

a. Only DMTZ_DGX is available:This topographic map originally contains only scarp lines and elevation points, so the DMTZ_DGX layer must first be generated using the CAD plugin.

b. In the topographic map, Area A contains only scarp lines and elevation points, while Area B contains contour lines. The boundary between the two areas is clear. The DMTZ_DGX layer is generated from Area A using the CAD plugin, and Area B uses the original contour lines.

c. Similar to case b, but the boundary between the two areas is not clear.

Use the Delete entities within and outside the range of closed polylines command in the CAD plugin to remove the contour lines within the Area A.Finally, generate the terrain in SketchUp using the method described in case b.

Import Geo TIFF file to create terrain

In addition to DWG files, GeoTIFF files can also be used for terrain generation.files.

The GIF below shows the process of creating terrain from Geo Tiff file：

Users should set a large number of elevation points for creating terrain by using TIIF file, such as over 300000.

Click the Settings button to configure the relevant parameters. These settings are generally not required, and only need to be configured when redundant surfaces appear in the generated terrain. For details, contact customer service.

After selecting the GeoTiff file as the data source, select the corresponding TIFF file. The creation range, key areas, and other parameters can be selected as needed, or left unselected.

When using the GeoTiff function, the default number of terrain elevation points shall be at least 200,000. The terrain elevation points are valid only when their number is greater than 200,000.

Other subsequent operations are the same as those for importing contour design projects.

Set origin coordinates

Manual setting of origin coordinates is not required when importing TIFF files to create terrain (ensure the origin coordinates in project settings are set to 0,0,0). The correct origin coordinates will be assigned automatically after terrain generation.

Importing Available/Restricted Area Range from DWG Files

The GIF below shows the process of Importing Available/Restricted Area Range from DWG Files：

Create a new layer in the DWG file, and draw a rectangle using the origin coordinates mentioned above as a reference point:

Enter the RECTANGLE command.
Enter a coordinate value such as 34613750.5817,2872899.9104 as the upper-left corner point of the rectangle. Press Enter, then select any point as the lower-right corner point.Save the DWG file.
Import the DWG file into SketchUp. Use the Move tool built into SU to move the imported DWG group to the SU origin point, with the upper-left corner of the rectangle as the base point.

Download satellite terrain and textures in Candela3D

Users can draw terrain range, available and restricted areas on satellite maps,download satellite elevation data,create terrain, and mark available and restricted areas.

Users can separately import available and restricted ranges from *.kml files, download satellite elevation data, generate terrain, and mark corresponding areas.

For terrain created from existing topographic maps, users can generate satellite map textures by clicking the Texture button.

Create terrain in SketchUp

If users need to arrange arrays on a special ground such as a flat or curved surface, they can use SketchUp's modeling function to create their own terrain.

Create flat terrain in SketchUp

Step 1: Please enter SketchUp, create a new layer and set it as the current editing layer. In this example, the name of the new layer is Ground (if no new layer is created, all subsequent operations will be performed on the default layer Untagged).

Step 2: If users need to create a flat ground, first switch the view to Top view in the Camera - Standard View. Users can also use the Top view icon in the toolbar to switch.

Step 3: Please use the line tool todraw a closed polygon on the XY plane in the top view according to the desired shape, making sure that the drawn polygon is closed and automatically forms a face. Users can also use tools such as rectangles or circlesto directly draw the corresponding shape surface.

Step 4: At this point, the surface cannot be recognized as terrain by Candela3D. Users need to enter the Create terrain button, select the Ground layer from the drop-down menu after Contour layer, and click Confirm.

Step 5: The software will automatically create a Terrain layer and create Candela3D recognizable terrain on that layer.

Building other types of terrain (such as arch bridge) in SketchUp

If other types of terrain are needed, SketchUp's own modeling function can be used for modeling. In this section, it will use the example of creating a new curved terrain to illustrate.

Step 1: Firstly, please switch the view to a side view and select one of the four side views, Front, Back, Left, Right, from the Camera - Standard Views as needed, or choose the corresponding icon in the toolbar.

Step 2: Please select the arc tool and draw an arc as needed.

Step 3: The specific parameters of the graphic can be entered in the lower right corner of the interface during the drawing process.

Step 4: Please use the line tool to connect the two endpoints of the arc to form a closed surface.

Step 5: Please click on the push-pull tool and use it to click on the surface created in step 4, then push the mouse to push the closed surface into a curved body.

Step 6: Please use the method described in 10, convert the graphic into terrain that Candela3D can recognize, and the resulting terrain is shown in the following figure.

Delete redundant terrain faces

User can use the Candela3D Advanced - Delete Terrain Faces tool or the Candela3D Drone - Cut Group tool to delete redundant terrain faces, especially those that may obscure the terrain.

Adding or replacing terrain

Adding terrain: Create the adding terrain in the Create terrain interface, then click No in the pop-up dialog.

Replacing terrain: Create the new terrain directly, then click No in the pop-up dialog.

Analysis