This module describes in some detail the steps taken in moving a gCAD+ drawing of a reasonably large site into the SketchUp environment. This is a design for quite a large site measuring some 400 meters across. The figure below shows an early stage in the development of the site drawing in gCAD+.

As delivered

The dotted lines showing to the exterior of the site are construction lines (XLINES). They are not needed in the SketchUp environment so the first step in preparing this gCADPlus design for SketchUp is to move those to their own layer and turn that layer off.

One other thing we noted was that the Object snap settings have been left in a state that is going to make it difficult to select entities and move to SketchUp. All snaps were on. So we cleared them.


Notice that much of the design is aligned with the main building. 


In order to make life in the SketchUp environment much easier, we will rotate the gCADPlus drawing such that these major axis lines run horizontally and vertically. To do that, we need an accurate angular measurement. Use the UNITS option to increase the number of decimal placed for reporting angles. 4 decimal places should be enough for our purposes.


Selecting one of the XLINES gives us an accurate angular measurement of 64.6175 in the Properties box.


We use the Select All option and rotate at an angle of minus 64.6175 (-64.6175) using coordinate 0,0 as the base point.

Select all



Now everything is squared off. This is not an essential step, but it means that the rectangle command can be used to place surfaces in SketchUp rather than the tedium of drawing lots of individual lines. It may even be that handling the gCAD+ drawing becomes easier.

Rotate 2

Next we will take the opportunity of rotating and aligning the scale bar. While doing that, it may be worth creating a new hand lettered font text style so we can use Windows text in the gCADPlus drawing. The reason for doing that is because text find can be used in a PDF file printed from a gCADPlus drawing. That might be very useful in a site of this size because the client can search for text and zoom in to that area to see more detail.

Scale bar

The main building on the site has been created in gCADPlus using a series of hatched parts. Hatching sometimes creates problems in SketchUp so we will make a single polyline for the building foot print setting fill on at completion of the polyline. Since the building is square, and we have a mud map of its dimensions, it is a good idea to turn polar on so the polyline denoting the building consists of right angles. An even better idea would be to make the drawing of the building as a separate drawing, inserting it as a block later.


The next step might be to load a plant data file and tag both existing and new planting because gCADPlus can pass details of the location of species into SketchUp. that helps build the SketchUp model.

We use plant tools to load a plant data file as shown below.

Load data file

gCAD+ allows us to create a new file.

gcp file

Or load an existing gcp file. Since this site is located in suburban Paris, we attach a list of plants suitable for that area.

Paris gcp

We now want to tag the existing trees on the site so we will isolate the existing vegetation layer.

Existing vegetation

You may remember that the plant list is easily sorted. Since the majority of species on site are trees, we will sort the list into large trees first.


Now we are ready to tag the existing trees.

tag trees

We use the show tagged plants option in the plant tools set to make sure all existing plants have been tagged.

All tagged

Here is the result. Clearly all species on the layer existing vegetation are tagged.

all tagged

Next the layers for new planting are switched on - Arbres and Vegetaux.


and isolated.

This revealed a number of symbols on the incorrect layer. The MatchPropertis tool was used to correct that error.

Match properties

Next the new planting symbols were tagged.

new planting

And a quick plant schedule generated. Note that gCAD+ counts the number of plants used in each category.

Plant list

As it stands, the list includes both new an existing plants. This is useful because we will want to find (say) a 3D plant symbol for a Dogwood and be able to locate it at the correct spot in SketchUp.

We are now ready to move the design to SketchUp.

Use the Mkae SketchUp layers tool as shown below.

Make SketchUp layers

In this instance, you would choose to export the text from the plant schedule. That text will be used to mark the position of each plant in the design. Here is the result.

For SketchUp

Select export DXF

Write DXF

If for any reason the DXF file cannot be created, simply select all and copy to the clipboard. 

To clipboard

Paste into a new drawing (do not use a template when you start the new drawing). You should be able to save a DXF or DWG file from this new drawing.

It is time to start SketchUp and insert the DXF file from gCAD+.

TIp: make sure that you start with an appropriate template in SketchUp (architectural mm in this particular case)

SketchUp units

Note:  If you purchase SketchUp Pro, it will allow importation of both types of file - dwg and dxf. Some early versions of SketchUp can be 'patched' to allow DXF import, but in their native form not every version of the free SketchUp will allow importation of DXF files (or DWG files for that matter). We have some experience with the free version of SketchUp 7. If you have a copy of Google SketchUp 7, you may be able to find on the Internet an application called AllowDWGImportInSketchUp7.msi. If this application is run SketchUp 7 now has the ability to import DXF. Unfortunately, We have no experience with this tool in other SketchUp versions. It may not work.

The information from gCAD+ as either a DXF or DWg file comes across to SketchUp as a block (one object). We recommend that you leave it as a block (even though it is possible to explode it) and use the SketchUp tools (rectangle, arc, line etc.) to draw over the top of the transferred block. This is quite easy to do because SketchUp automatically finds the control points even though the transferred block remains intact. The important thing is that you do not need to use the clumsy draw tools in SketchUp and redo your design. The accuracy is implicit in the transferred drawing. I do not have to worry about drawing accurately in SketchUp to get size and proportions correct. The hard sizing work has been done in gCAD+.

Note: SketchUp see entities differently to CAD software like gCAD+ and AutoCAD. As shown below, an arc for example, when imported into the SketchUp environment, is broken up into a series of short line segments. We are working on giving gCAD+ the ability to save a SketchUp file directly, but it is not ready yet.

Arcs become lines 

It is possible to explode the block and if everything has been perfectly drawn in gCAD+, you can often use the push/pull. Many times that does not work because of small errors in the construction of the gCAD+ drawing. No one notices in gCAD+, but SketchUp being an architectural package, expects lots of accurate straight planar surfaces.

Here is the gCAD+ model inserted into the SketchUp environment. The rectangle and Push/Pull tools have been used to raise the height of the building.


Tip: It does pay to return to the gCAD+ model as soon as you have satisfied yourself that the export to SketchUp works smoothly.

For example, as shown in the figure below, we have added some extra detailed design work to the area near the vegetable gardens. A 230 mm header brick layer has been added to the raised walling and one of the vegetable beds has been detailed. Adding extra detail makes it much easier to create the SketchUp model.

Add detail

Here is the information in SketchUp with the gCAD+ information as a base for 3D SketchUp information.

in SketchUp

Movie Movie  Here is a small movie to show how the model shown above was created.

Once the base data is loaded, you can now use all your SketchUp skills to build a 3D model, place 3D trees and shrubs, add materials, render, etc. Remember that SketchUp is a complex application, at least as complex as gCADPlus. The more you learn about SketchUp, the better will be your 3D models. ** You have taken our online course on the use of SketchUp haven't you! *** 

Adding trees and shrubs

Because the location of trees (and species type) are known, it is easy to place them in SketchUp.

Adding 3D trees

Better than taking models from the 3D warehouse, try making your own with applications like 3D Tree Maker. It builds 3D trees. 

To install 3D Tree Maker:

1. Download the plugin and save it to your PC

2. Run Sketchup. Go to "Windows - Preferences". Clic on "Extensions", and then on "Install Extensions..." button and select the plugin file you just downloaded (file 3darcstudio_tree_v1.05.01.rbz).

Install from zip file

If the Sketchup version you use does not support extensions installation, you can setup the plugin this way :

1. Download the zip file to your disk.

2. Unzip the file on your disk

3. Copy the file 3darcstudiotree.rb" into the Stetchup "Plugins" directory.

4. Copy the directory "3darcstudiotree" into the Sketchup "Plugins" directory.

Case study