Learning Rhino 3D. Modelling a fork

Transcription

1 > Background images - use PictureFrame command to load top and side images of the fork. Place the top image in the Top viewport and place the side image in the Front viewport.

2 > Scale images - you will need to scale the image so that the picture has the same dimensions as the real world object. Measure the fork, draw a line of that length and use it to scale the image. Place the images on their own layers i.e. one for the top image and one for the side image. Lock the layers.

3 > Draw top curves - use the Interpolate Curve to draw a line following the contour in the top view. Use the Edit Points command to move the curve points around to accurately follow the edge. Draw a line through the centre. You can then use the mirror command to mirror the edge curve (remember that the photo will show perspective so the line may not line up perfectly when mirrored - don t worry - it s just important that it s symmetrical).

4 > Draw side curves - switch to the front view and draw curves which follow the top and bottom edge of the side image. Use the Edit Points command to make small adjusments.

5 > Copy side curves - Copy the side curves and move them over (seen in perspective view below).

6 > Copy side curves - When you copy the side curves, move them so that they are wider than the original image.

7 > Cross section curves - Use Interpolate curve to draw lines from one set of side curves to the parallel set. You can then turn on the edit points to adjust these curves.

8 > Cross section curves - Use Interpolate curve to draw lines from one set of side curves to the parallel set. You can then turn on the edit points to adjust these curves.

9 > Cross section curves - Make a complete set of cross-section curves (shown in orange below).

10 > Top and bottom surfaces - Use the Sweep 2 Rail command to make surfaces. The green lines are the rails and the orange lines (shown in the previous step) are the cross section profiles. Repeat this command for both the top and bottom surfaces.

11 > Side surfaces - Select the top curves you created earlier (page 3). Use the Extrude straight command to create surfaces from these curves. The extrusion distance isn t too critical - just make them longer than the eventual sides of the fork.

12 > Trimming surfaces - You should now have two sets of surfaces - one set created from the top view and one set created from the front viewport. Using the trim command, use the top view surfaces to trim away the excess material from the side surfaces. For this to work, the top surfaces need to extend beyond the side surfaces (use the Extend Surface command to extend the surface if they are not currently long enough). Use these surfaces as your cutting objects Trim away the excess on either side of the trimming surfaces.

13 > Trimming surfaces - After doing the trim, you should be left with a model as shown below.

14 > Trimming surfaces - Draw curves (in the top view) for the ends of the fork and extrude these into surfaces. You can then use these to trim the fork to the correct length.

15 > Trimming surfaces - In order to create the sides to the fork, repeat the trim command but this time use the end surfaces and the top and bottom surfaces (shown in yellow below) as the cutting objects.

16 > Tine curves - Create curves in the top view for the tines (prongs) of the fork. Make one side and mirror.

17 > Tine surfaces - Use the extrude straight command to make surfaces for the tines (shown in perspective viewport below)

18 > Trimming the tines - Use the trim commad to cut the tines. The green surfaces below are the cutting objects.

19 > Adding fillets - In order to fillet, you need to join the trimmed surfaces together. Go to the Join command and then select the surfaces you want to join. You can then use the Fillet edge command (solid/ fillet edge in the top menu), to fillet (ie add a radius) to the edges.

20 > Adding fillets - For the ends of the tines, first create surfaces using the Surface from 3 or 4 points command. Join these surfaces to ther rest of the model and then fillet.