• TechNotes
• Sketch Rendering from Floor Plan

TechTip Winner of the Month of January 2003

Submitted by KarlOttenstein, USA

The TechTip July 2002 winner, BertNijs, from Belgium found a way to show Floor Plans in the 3D Window inspired Karl to find a way to create a sketchy look of 2D drawings of ArchiCAD (Floor Plans, Section-Elevation Windows etc.) The idea came after a user wanted to be able to achieve results similar to those created by the Sketch Rendering Engine of ArchiCAD on the Floor Plan. Some additional data need to be taken into consideration to achieve a correct result. Basically what we need is to have an ArchiCAD Library Object at the end which contains 2D lines in its 2D View and real 3D lines in its 3D View. Several steps are needed to achieve this, but here is how to do it (The examples were done in ArchiCAD 8 and PlotMaker 3):

1. Select all layers that you want to be visible on the final rendering and hide the rest.
2. It is a good idea to draw a rectangle or place 4 hotspots around the 2D drawing data as later you will need it for easy placement and resizing.

3. Let's say you want to create a Sketch Rendering of an Elevation of your Project. Generate the Elevation. Then Save a PlotMaker file from the Elevation. (e.g. "North Elevation.pmk")

4. Plot the Elevation into a file, using any HP Plotter Driver (preferably HP 650C). Name this file (e.g. "North Elevation.plt"). Use the settings as shown in the screenshot below. Make sure that you note down the scale at which you saved this PLT file as you will later need to enlarge it back when saving as DWG.
   
   The reason you might need to save two files is this: The Pen Sets of ArchiCAD 8 and PlotMaker 3 can be different.
   (The reason you need to save the Elevation as a PLT file is because it breaks down everything into lines and arcs, which is what we need at the end. If you save in other formats (.PMK, DWG, DXF etc.) fills remain fills, texts remain texts and at a later step when we open the saved file as an ArchiCAD Library Object the fill pattern lines and texts will not be visible in the 3D View of the Object, only in 2D View. Hence the PLT file.) But when you save a PLT file, no pen indices are saved, only RGB values of pens. When in the next step the PLT file is placed on a PlotMaker layout, the program will encounter RGB values for lines in the PLT file, will look up which Pen in its own Pen set is the closest match and set the pen index of that line to point to that pen number. So you may save a line which is Pen 8 in ArchiCAD and it becomes Pen 175 in PlotMaker because of this. The solution is to make PlotMaker have the same Pen set as ArchiCAD does before placing the PLT file onto it. Hence the following steps.

5. In PlotMaker, create a new Layout Book and import the PMK file that you saved. The PMK file contains all PEN definitions of the original Elevation. Place the PMK file on the Layout.

6. Now with ALT-click on Windows, OPT-click on Mac, pick up the attributes of the PMK file from one of its corners. Then find one corner of the Layout (the blue rectangle) and with CTRL-ALT-click on Windows, OPT-CMD-click on Mac, transfer these attributes to the Layout. The following small dialog box will appear:
   
   Check both PenWeight and PenColor and click OK. Now if you check the Pens & Colors of the Layout you will see that they are the same as those of ArchiCAD.

7. Import the PLT file to the Layout.

8. Open the PLT file in PlotMaker. (You'll see that everything is broken down into the most primitive elements (lines, arcs, hotspots). This is necessary in order to see them later in 3D.) Save it as a DWG file. Use the settings as shown in the screenshot below:
   
   Make sure to save only visible layer since if you don't they will be included in the DWG file and can be part of the final result as well cause undesired drawing elements. For pen, select the "keeping pen index number" option so it will give the correct colors. Also, be very careful about Drawing unit at this save operation. If you compare the PMK and PLT files on the Layout you will see that the PMK file is at the scale you saved it from ArchiCAD, but the PLT file is at the scale of 1:1 because it is simply a file already reduced by the scale you set when you saved the PLT file. Now you need to set the correct drawing scale. For example, if you saved in a scale of 1:50, one meter in the drawing became 20 millimeters in the PLT file. So now you have to specify that 20 millimeters in the PLT file will equal to 1 drawing unit in AutoCAD.

9. Now open this DWG file in ArchiCAD. Use the settings as shown in the screenshot below:
   
   Again, select the above choices and make sure to choose the "keeping pen index number" option for pens. Also make sure to set the drawing scale back so that 1 drawing unit in AutoCAD equals 1 meter in ArchiCAD. So if you did the previous step correctly, the DWG file is now in the correct scale and you don't need to bother with scaling when saving and opening the DWG file. Now in ArchiCAD you might want to do any modifications needed before again saving it as DWG. For example, you might want to move to whole drawing closer to the ProjectOrigin or delete unneccessary HotSpots that have been generated.

10. Save this file as a DWG file. You can also overwrite the previous DWG file saved from PlotMaker. Use the settings similar to your previous DWG save.

11. Open this file as a Library Object in ArchiCAD. At this point you will need to make a small modification in the ArchiCAD Library Object.
    
    There is a problem currently in the program which generates two lines incorrectly. These are the MUL2 a,b line in the 2D Script. This assumes the A and B sizes of the newly generated Library Object are both 1.0 and therefore stretch it incorrectly, The same thing happens in the 3D Script. So you need to divide them by their default values. So in the example below the first line of the 2D Script would change to this: MUL2 A/40.0050, B/13.4650. Also, the second line of the 3D Script would be: MUL A/40.0050, B/13.4650, ZZYZX. It is a good idea to set Dimension Units to 4 decimals in the Preferences dialog box so you will have accurate results. In earlier version of ArchiCAD this was not a problem and the program generated the Scripts correctly).
    When this is done you can save the Library Object under a new name.

12. Now you can select the Library Object to place it. Make sure to check the 'Use Symbol Color' checkbox in the Object Selection Settings Dialog so they will appear in the same colors.
13. Select the Object. Go to the 3D Projection Settings dialog box. The below picture shows how the Object will look in 3D in isometric projection. You should select Top View so it will look like an Elevation in the 3D Window.

14. Go to the PhotoRendering Settings dialog box. Select the Sketch Rendering Engine and click the Options... button to enter its Subdialog where you can select and customize the kind of Sketch Rendering you want to apply.
    Also, set the desired PhotoRendering size and background colors for your Rendering. You may also find the file "SketchPreset.txt" located in the "Add-Ons / Visualisation / Sketch Textures" folder. You can copy and paste a whole Preset into another portion of the file and modify it to your preferences or save in it a Sketch setting set that proved great-looking for you. Make sure to create a copy of this file before you start modifying it. Here are some final sketch results from a Floor Plan of another Project:
    
    
    

Note: When selecting the Sketch style to be used, please make sure that you set the "Air perspective" value under the "Enhancements" section to 0%. Any other value will not give correct results. The reason is because when you use a Parallel projection (such as Top View) the sketch rendering engine doesn't have information about how far the 3D data is from the viewpoint. It is as if it was at an infinite distance therefore any Air perspective value will make the lines disappear in the Sketch rendering.

CategoryRendering