When AutoCAD Map 2007 was released with its new FDO (Feature Data Object) engine I found the transparency functionality and thought – ‘excellent see-through data!’. There was a catch however, although it’s great for polygons, I have never been able to make raster data transparent – until now!!
Through some useful posts from the community on the AutoCAD Map discussion forum; and through some trial error, I can now make my raster images transparent. This is how to do it……..
Step 1 – Add the raster image to the DWG through FDO
Open the ‘Data Connect’ menu found on the ‘Display Manager’. Once in the editor, select ‘Add Raster Image or Surface Connection’, navigate to the file you wish to connect to and then tick the box and hit ‘Add to Map’.This will add your raster image connection to your DWG.
As you can see from the screen captures above, the image displays in the correct location as AutoCAD Map understands its associated ‘World File’. However it has been placed in front of the stadium design CAD data, hiding it.
Using the Display Manager I am able to manage the draw order of my data in Model Space and could force the image behind the CAD data. In future posts I will explain the tips for doing this. In this example however I want to make the image transparent.
Step 2 – Save a ‘Layer file’ for the image
A Layer file is an XML based file that you can export from AutoCAD Map for any FDO connection you have made in the Display Manager. Within the file it will save all the styling information and it also records the location of the data source e.g. Location on disk of the Raster Image file. Once the file has been created you can add saved Layer files into any AutoCAD Map DWG to re-use them – making it very easy to connect and style the data.
To create a Layer file for the raster image that has been connected simply right mouse click the layer on the Display Manager and select ‘Save Layer’
It will prompt you for a name and location to save the Layer file.
Step 3 – Edit the Layer file to enable the transparency.
To make the image transparent you need to add a extra line to the Layer file. In Windows Explorer, navigate to the Layer file that has just been saved and open it in Notepad.
This is the data contained within a Layer file.
To add the transparency setting, find the line that defines the ‘FeatureName’. Its usually about 22 lines down in the file.
It looks like this:
Underneath this section on a new line add the following…..
0.5 being the degree of transparency – 0.1 is very transparent, 0.9 is not very transparent.
This is how your file should look:
Once you are happy, save the notepad file.
Step 4 – Add the Layer file to AutoCAD Map DWG.
Now you have added the transparency in the Layer file you can add the Layer file to your DWG.
Turn off any other Raster Imagery in your DWG. From the Data button on the Display Manager select ‘Load Layer’ and point to your Layer file.
This will add the Raster Image to the Display Manager in the same way as doing a Data Connect would do, except this time the transparency should be activated.
You now can see the Stadium CAD data below the image.
Check back for more soon!