Sections -- Rhino+Ai

Tutorial by:

John Greene (gree1609@umn.edu)

Software used: Rhino 5.0, Illustrator CS5, Flamingo nXt

Once you have a model in Rhino you can produce good sections with ease using vector lines or rendering! The Rhino command names cited in this tutorial in italics are formatted to input in the command line, but they can also be found in the drop down menus. Before you begin, copy your file because we will be slicing and manipulating.

1) Make a vertical plane representing where you are cutting through the object(s) for the section.

2) Use IntersectTwoSets to extract the cut lines for your section. The command will ask you for first and second sets of objects to intersect; one set will be the cutting plane and the other will be your object(s). IntersectTwoSets will give you a set of selected intersections that are the cut lines for your section, before de-selecting the cut lines remember to move them away from your model so they don't get lost amongst all the other information (the IntersectTwoSets command will place the intersections on your current layer).

3) Determine which direction your section is facing and go to the appropriate front, back, left or right viewport. From here, use Make2D to create a drawing of your cut lines that will show up on your world top c-plane. The Make2D command gives you a dialog box with many options; make sure you create a layer for the visible lines. Now go to top view and if you haven't already scaled your section do so now. Center your 2D drawing on the origin ({0,0,0}), then select all of the line work and go to file -> export selected. Choose the Adobe illustrator file type from the drop down menu and save. Note: if you don't move your 2D drawing close to the origin before export selected, then you will not see anything in your illustrator file (the center of your illustrator file is always the origin from Rhino).

4) Now that you have your cut lines as a .ai file the next step will be getting the elevations beyond the cut lines. To get this information, you will actually cut your model at the section plane leaving a cross section of the object(s). Slice your 3D model with the section plane using the Split command; first it will ask for objects to split and then a cutting plane. After Split finishes, select the objects that are not included in the background elevation and move them out of the way.

5) Go back to the viewport that represents the direction you are looking in your section (beginning of step 3 above). Since the background elevations have depth, you have the option to represent them as either parallel line or perspective projection. To do this, right click on the viewport name, go to viewport properties and a pop-up menu will give you the options for projection systems. For this tutorial we will continue with parallel line elevations. Now select the elevation background objects from your section of the model and Make2D. Go through the same steps from step 3 above to create a layer for your background elevations, scale, move the drawing close to the origin and export as an illustrator file.

6) Open illustrator and open the cut lines and background elevation files. You will see that your illustrator preserved the layers you created when you made the 2D drawing in Rhino. Overlay the two sets of lines exactly on top of each other. Select all of your cut lines (by clicking on the circle to the right of the layer name in the layers panel) and give them a heavy line weight, then select your background elevation lines and give them a much lighter line weight. To get this right you will have to print your section to ensure that all line work is reading correctly.

Rendered Section

1) If you want to do a perspective section then go back to step 5 and in viewport properties select perspective projection. You can continue with the method used above to get cut and elevation lines into illustrator for a more traditional section. However, if you want to start to capture light distribution and depth of space, then you can do a rendered perspective section. For this tutorial, I am using the newest version of rendering software developed by McNeel: Flamingo nXt (see link at bottom of page for tutorial and free beta version). Starting where we were in step 5, go to the appropriate viewport and click on the Flamingo nXt tab on top of your screen. First, click on the materials tab and select solid color. Then click on lighting and choose your desired lighting method; here I chose exterior daylight and I changed the azimuth and altitude of the sun in order to illuminate the space through the windows. Next, click on environment and the only thing I will do is set the background to a solid color not found anywhere else in the rendering so it can be easily manipulated in photoshop for background images. Now click on the render tab and tell Flamingo what view you want to render; in this case I am using my active viewport. You are now ready to render; just click the render button on the tool bar (highlighted in the last picture above).

2) Once you press the render button, a window will pop up and show the rendering process. It will keep rendering until you press the stop rendering button in the top right of the window. After you stop the rendering process, save the image and take it into illustrator to add the cut lines.

3) I decided that I will poche the cut areas (fill all the cut geometry with solid color). Open the image in Illustrator and paste the cut lines onto the art board then scale them to fit on top of the image. In this case the cut lines will be used to fill with solid color for the poche. Since we are using poche, it will be best to treat the ground the same way and fill it in with the same solid color.

Links

Flamingo nXt tutorial: http://tips.rhino3d.com/search/label/nXt