Rhinoceros Car Modeling Tutorial

Transcription

1 Rhinoceros Car Modeling Tutorial This tutorial will guide you to car nurbs modeling process using Rhinoceros 3.0. To start a car modeling you will need some car images (or sketches) to get an idea of the car surface shape and blueprints.

2 Blueprints (or accurate hand made technical car views).

3 Set document units to centimeters. Set the grid extents to 250 and minor grid lines to 2. Or turn the grid lines off. We need to place the blueprints images in the viewport background. To place the blueprints in proper size we need to know the car measures: length, height, wide, etc. The blueprints must be cropped until the image edges touch the car drawing lines, doing this will make easier to place and scale the blueprint in the appropriate position. We will place the front car view in the front viewport; we will use car height as reference to place the bitmap. And we will locate the image aligned and centered to the grid (cplane) axis. Place the background bitmap in the front viewport. Don t worry about the size and location we will locate it more precisely later. Once you have placed the bitmap use the move background bitmap icon to place the car symmetrical axis line aligned with the cplane Y axis. You can achieve this by looking the bitmap cross lines generated when you move it. Place the crossing line over the green axis (to use this method your background bitmap image must be cropped until it touches the car drawing extension). Move it up and down until the wheels touch the cplane X axis (you can use shift key to constrain the movement direction)

4 The final step is scaling it until it reach the desired height. Draw a line from 0,0 with 134cm length (car height). Use the scale bitmap and use the line as reference to achieve the desired height. You can also use align background bitmap command to achieve the desired size. The car now should be 184cm wide approximately. We can draw a line to check the car width. Use a different color than the one used in the background bitmap. Ok, Align all the background images using the same method, but be careful, is this steps are not done properly you will encounter a lot of problem later trying to model curves using the views as references. Use the vertical line (134 cm long) lo scale the lateral blueprint in the right view. Scale the background image using the car height as reference. It will determine the car length (425 cm) Place the lateral blueprint in position, the wheel touching the cplane X axis and the front bumper touching the Cplane Y axis. Create a line 425 cm long from the cplane origin. We will use that line as reference for the top viewport blueprint positioning.

5 In the top viewport you can use the width reference line (184cm) and the length reference line (425 cm) to scale the background bitmap. Use align background bitmap command to achieve the desired background size. This is how the viewports should look like.

6 The next step is maybe the most difficult to perform. We will create the car side with just one surface, it will be cut later to achieve its final shape. We need to create a few sections and 2 or 3 rails to guide the surface creation. Create the curve with less control points as possible. Use the control point weight command if necessary to avoid extra control points. Use the curvature graph command to verify the curves curvature and simplicity. You can find more information about fairing curves here. Fairing Curves and Surfaces (Acrobat Reader needed...) Everything about fairing for marine designers. The curve creation is very complex and it will require you to go back and forward several times until you achieve the correct curves in the correct position. Use car images or photographs as reference to your curve creation. You must use your 3d thinking mind here. This section generation can take a lot of time and patience. There are a lot of curve control point adjustments to be done until we get the desired sections. We will create the car lateral surface using surface from curve network command (this is because we have in this case 3 rails to guide the surface). Note here that the surface is over build we will but it will be trim later. You can check the surface shape by projecting curves to the surface. The projected curves should look like the blueprints curve is all viewports; this will show you if the surface it has the correct shape where the curve is projected. You can see in the image to examples of this surface verification method. The lines created in the right viewport were projected to the car lateral surface.

7 The projected line was compared then in all viewport with the blueprints. If the projected line fits in all viewports with the background bitmap lines then the lateral surface in that car area has the correct shape. You can use the hood opening line, the trunk line, the windows base line and the door opening lines also to check the surface shape. There is a lot of try and error before getting the desired surface. The complexity of this surface creation depends on the car shape. I other cars a simple sweep 2 rails surface could create the lateral surface. Once created the surface, trim it with curves to get the desired result. You can extrude the curves and split the surface or directly split the surface with the curves in the right viewport. Create the lines in the right viewport.

8 Extrude the lines. Split the surface

9 Create the line in the right viewport and extrude it. Split the lateral surface

10 Create the line and extrude it. Split the surface.

11 Lateral surface before trimming. Lateral surface after trimming. Note that the upper and rear surface parts were not trimmed. Those will be trimmed later on the tutorial. Once created the side surface, we will start modeling the cabin. We will use the blueprints lines as references and use curve from 2 views to create the rails for surface creation. Create 2 planar curves (red lines) on top and right views using the blueprints as reference, extend the lines beyond the blueprint endlines, then use Create curve from 2 views to create the 3d curve.

12 This is the 2 planar curves perspective view and the blue line is the result of combining both with Curve from 2 views command. After the 3d curve is created you have to rebuild the curve using the refit command to decrease the number of control points. Remember that you still need the 3d curve to follow the blueprints curve shape.,

13 Run the refit command using 0,1 tolerance to reduce the control points on the resulting curves, but avoiding too much deformation. Before Refit command. After Refit command. If the curve after the refit command still has too many control points use the rebuild command to reduce them. Be very careful about not to deform the curve shape too much. Create the roof sections to guide the roof surface when using surface from curve network.

14 Use the cutplane command and then intersection command to obtain the 3 points for middle section creation. Use Curve:interpolate points command to create the section curve. Use surface from curve network to create the roof surface. Note that surfaces (car lateral surface and roof surface) are overbuilt and intersected with each other. They will be trimmed later on this tutorial.

15 Create on the top view the windows base line (extended) Project the curve to the car lateral surface on Top viewport. Or extrude the curve and use the intersection command to create the windows base line.

16 Create in the right view the windows upper line (extended). Extrude it until it pass over the projected windows base line. Trim the windows base line with the extruded surface. Delete the extruded surface and the splited curve ends. This will leave the windows base line in its proper length.

17 Create the windows upper curve with the curve from 2 views command to use it as a reference curve for windows surface creation. Create the windows surface with the extrude command using the along curve option. Split the extruded surface with the windows upper line curve and check how apart are the windows surface edge from the curve from 2 view curve. Delete the extruded surface, modify the section curve for the extrusion and extrude it again (along curve option). Split the surface and check again the distance between the surface edge and the curve form 2 views curve. This will require some trial an error until the trimmed windows surface edge become similar to the curve from 2 views curve.

18 Use the intersect commad to create the curve where the roof and the lateral surfaces intersect Create a blend curve

19 Edit the blend curve points to get a smoth curve. You can not move the 2 nd control point from each end, Because that will make the curve loose its tangency direction. Because some control points were deleted. Rebuild the curve with at least 6 control points. This is necessary to achieve the desired surface continuity when using surface from curve network or sweep 2 rails. Project the edited curve, if necessary on the lateral surface.

20 Repeat the steps on the A pillar. Create a line and project it to the roof and the windows surface.

21 Create a blend curve between the projected curves. Create the pillars surface using sweep 2 rails with the tangency option checked were possible. Shade the resulting surfaces in tangent continuity is not good enough all over the surface create more sections along the pillar to guide more precisely the surface creation.

22 Add more sections if necessary. Create the surface using sweep 2 rails or surface from curve network command.

23 Create a mirror surface from the pillar and the lateral surface. Join the roof surface to the pillar and the windows surfaces together and use the zebra analysis to check for surface continuity issues.

24 Check for the help file and the manual about zebra analysis mode. Now we will start with the hood surface creation. Split the lateral surface with a curve with the correct shape to create the hood side curve.

25 Crete a line and project it to the lateral surfaces we will use the projected lines to create the first hood section. Create a line using the blend command and move its control points to get the desired shape. Remember always move symmetrical control points at the same time to keep the symmetrical curve shape, and, if you need to move the second control point of each end, use the adjust end bulge command with the curvature option off. You will have to create some auxiliary geometry to move both control points to the same symmetrical position.

26 Extend the car lateral surface edges curves using the smooth option. We will use them later to create the hood front surface. Create a blend curve. Edit its control points if necessary.

27 Create the surface using sweep 2 rails (cleaner surface). Run the zebra surface analysis command to verify surface continuity.

28 Create a new line from the extended curves endpoints and edit the control points until it fits to the blueprint in the top view Extend the lines.

29 Create a sweep 2 rails Create a blend surface Perform Zebra analysis Delete unnecessary surfaces