Nurbs Modeling Introduction

Introduction and Preparation

This tutorial guides you through the creation of a facade detail. The detail is a derivative from the facade construction of Seattle Tacoma Airport. In this tutorial the detail is modeled using NURBS geometry. It is an introduction to modeling with NURBS geometry and shows most common NURBS modeling tools.

Download the Maya-file from which we will start modeling. Download Save the file to your hard disk.

Open the file in Maya. Notice that a center piece is already modeled and some curves are present: two smaller circles and three larger circles. You will use of the provided geometry and curves to finish the model.

Before you start make sure your menu set is set to Surfaces. Use the drop-down menu to switch to the Surfaces menu set if necessary. And don't forget to save frequently to avoid losing work.

When modeling with NURBS you probably want to switch between the wireframe and shaded display modes quite often. This can be achieved using the keys 4 for wireframe and 5 for shaded.

Or through the Shading > Wireframe or Smooth Shade All menu of the panel menu bar.

This is covered in more detail in the Maya user interface page.

Modeling the glass holder

Select the smallest curve. Go to Surfaces > Planar and choose the optionbox.

Make sure the settings are set conform the image below and hit the Planar Trim button.

Select the two smaller circular curves. Then go to Surfaces > Loft and choose the optionbox.

Configure the settings according to the image below and hit the Loft button.

Select the larger curve of the two smaller curves again and go to Surfaces > Extrude and choose the optionbox.

Configure the settings according to the image below and fill out 1.250 for the offset distance. Click the Extrude button.

Select the curve again and duplicate it using Edit > Duplicate (or Ctrl+d).

Move the copied curve 0.25 units over the z-axis. You can do this using either the Channelbox or the relative transform input (make sure you set it to Relative transform):

The result should be as displayed in the image below.

Keep the copied curve selected. Duplicate it using Edit > Duplicate and adjust it's scale to 0.45 units (for X, Y and Z) in the Channelbox.

Select the original and the duplicated curve and choose Surfaces > Loft.

Select the duplicated curve. Go to Surfaces > Extrude and choose the optionbox.

Check the settings according to the image below and fill out 0.05 for the extrude length and click the Extrude button.

Select the three larger curves in successive order and go to Surfaces > Loft and choose the optionbox.

Configure the settings according to the image below and hit the Loft button.

Keep the newly created lofted surface selected and hold the shift key while selecting the extrude surface created in the earlier step. Both surfaces should be selected now.

Switch to Component Mode and choose line selection. Make sure none of the other options for component mode are enabled.

Select the edge isoparm on each surface by clicking on it. While clicking the second isoparm, hold the shift key. With both isoparms selected go to Surfaces > Loft and choose the optionbox.

Configure the setting according to the image below and hit the Loft button.

Switch to Object Mode. Select the curve positioned on the edge of the round lofted surface created with the three larger curves. Duplicate it using Edit > Duplicate.

Scale it to 0.2 units (X, Y and Z) using the Channelbox.

Select the original and the duplicated curve and choose Surfaces > Loft.

Select the tube object created earlier (see image below).

Go to Component Mode and choose line selection. Select the edge isoparm.

With the isoparm selected choose Edit Curves > Duplicate Surface Curves. Go back to Object Mode.

Keep the duplicated curve selected and choose Modify > Center Pivot.

Now scale the curve on all three axes to 2.2 units.

Still keep the curve selected and choose Surfaces > Planar.

Select the curve again and duplicate it using Edit > Duplicate.

Move the duplicate curve -0.05 units on the z-axis.

Select the original and the duplicate curve and choose Surfaces > Loft.

Select the duplicate curve and duplicate it using Edit > Duplicate.

Scale the duplicate curve on all axes to 1 unit.

Select both the original and the duplicate curve and choose Surfaces > Loft.

Keep the lofted surface selected and duplicate it using Edit > Duplicate and move it -0.1 units on the z-axis.

Keep the object selected and duplicate it another time and move it -0.05 units on the z-axis.

Hold the shift key while selecting the original object. Now both object are selected. Switch to Component Mode and to line selection. Select on both surface the isoparm on the outer edge. Hold shift while selecting the second isoparm.

With both isoparms selected choose Surfaces > Loft.

Modeling the connection

Switch back to Object Mode. Select the tube of the pre-modeled center part.

Switch to Component Mode and line selection and select the edge isoparm. With the isoparm selected choose Edit Curves > Duplicate Surface Curves.

Go back to Object Mode. Duplicate the resulting curve using Edit > Duplicate and choose Modify > Center Pivot.

Move it 1 unit on the x-axis (use the Relative Transform). Keep the curve selected and add the original curve to the selection by holding the shift key and clicking it.

With both curves selected choose Surfaces > Loft. Note that the resulting geometry does not fit within the modeled part.

Select the duplicate curve again and scale it smaller. Notice the geometry changes accordingly. Scale it until the geometry fits within the modeled part. It still protrudes the glass holder though.

Select both intersecting surfaces and go to Edit NURBS > Intersect Surfaces and choose the option box.

Configure the setting according to the image below and hit the Intersect button. Notice the 'curve on surface' that has been created on both surfaces.

Select one of both surfaces and choose Edit NURBS > Trim Tool. Notice the object is displayed in white dotted lines and the mouse pointer has changed.

Click on the part of the object that should be kept. A yellow marker appears. Hit enter to confirm.

Repeat the same procedure for the other surface. Select it and choose Edit NURBS > Trim Tool. Click the part which needs to be kept and hit enter. Now the surfaces connect perfectly without intersecting each other.

Finishing the glass hoders

Select all surfaces you have modeled (so do not select the center piece that was already modeled) and choose Edit > Group (or Ctrl+g) to group them together.

With the group still selected go to the top view and check that the pivot point of the group is placed in the center of the grid. If it is not placed on the center of the grid, move it there using Grid snap. Switch back to perspective view.

With the pivot point placed correctly duplicate the group using Edit > Duplicate and choose Edit > Delete by Type > History.

Now scale the duplicate group in the x-axis to -1 in the Channelbox. This will mirror the duplicated group in the YZ-plane.

Duplicate the selected group again using Edit > Duplicate and scale the group in the y-axis to -1.

Duplicate the group once again and scale it in the x-axis back to +1.

Now the model should look like the image below.

Adding the cable

Finally a cable is added to finish the model. Go to the side view. Go to Create > EP Curve Tool and choose the optionbox.

Make sure the Curve Degree is set to Cubic. Note that your Channelbox is replaced by the Tool Settings panel. You can switch back to your Channelbox using the icon at the top right corner.

Draw the curve by clicking the start and the end point in the viewport. Hold shift to draw a perfect vertical curve. Hit the Enter key to confirm.

Keep the curve selected and switch to Component Mode and point selection.

Select the middle two Control Vertices (the purple dots). Select the Move Tool and move the the Control Vertices. Notice the curve bending. Move the Control Vertices until the curve cuts through the geometry. Note that the display quality of the curve may be poor - not nicely curved but jagged -, depending on your Maya settings.

Go back to the perspective view and check if the curve is correctly modified. Switch back to Object Mode when satisfied. Create a new circle by choosing Create > NURBS Primitives > Circle (Make sure Create > NURBS Primitives > Interactive Creation is turned off).

Keep the newly created circle selected and scale it down to 0.05 on all axes.

Add the curve drawn with the EP Curve Tool to the selection by clicking it while holding shift. With the so called profile curve and the path curve selected in the correct order, go to Surfaces > Extrude and choose the optionbox.

Configure the settings according to the image below and hit the Extrude button.

The model is finished now and should look like this.

Additional related sources

This tutorial showed you the most common NURBS modeling tools. A full overview of more NURBS modeling theory and tools can be found here.