PAGE 2

We will now do things to the large central Polygon on the front face. Still in Perspective View, choose the Polygon Tool and the Live Selection Tool. With OSV ON in its Active Tool Manager, click on that Polygon to select it. Choose the Move Active Item Tool and drag the Z-axiz (blue) ARROW of the Polygon to the left to pull the Polygon out of the Object (left image):

Now de-activate the HyperNURBS Object in the Object Manager by clicking on its red tick to change it to a cross to get what is in the right image:

The rounding effect of HyperNURBS can be clearly seen in the first image. Of course, the dragging of the Polygon can be done on any Cube without the use of HyperNURBS - the result would be the same as in the right hand image.)

Activate the HyperNURBS Object again (click on its red cross) and note that the place where the Polygon joins the main part of the object is very rounded. Depending on the model being made, this can be sharpened and shaped by adding some more Edges and Scaling them, as follows. Change to Right View and use the Knife Tool again to create some more Edges as in the image. Select the Edges by using the Rectangle Selection Tool with OSV OFF (the image shows them selected):

Change to Perspective view and use the Rotate Icon in the Viewport to look at the effect all round the Object (left image): With the 8 new Edges still selected, and the Edge Tool also chosen, choose the Scale Tool. Activate the X-axis (Main Menu Bar > Tools > X-Axis/Heading) and de-activate the Y-Axis and Z-Axis (same Menu), or click on the three Axis buttons just below the Main Menu Bar so that the Y and Z Axes have no grey border round them. With the Edge and Scale Tools still chosen, drag the mouse pointer in the Viewport down and to the left to change the shape as in the right image: (This demonstrates the use of dragging the mouse pointer with the Scale Active Element Tool when one or more of the Axis Tools are deactivated.)

Now lets sharpen the end of the "nose". This could be done using the Edge Tool to create more Edges but we will use the Extrude Tool instead to do the same. In Perspective View, and with the Polygon Tool and Live Selection Tools chosen, select the end Polygon as you did before with the other Polygons. Use the Extrude Tool (Main Menu Bar > Structure > Extrude) (shortcut D). In its Active Tool Manager set "Offset" to 5 m. Press Apply, (left image):
Using the Extrude tool like this (with a small Offset) is a good way to sharpen the shapes. The new Polygon at the very end of the nose will still be selected. Make sure that all of the X-, Y- and Z- Axes are activated using the way mentioned above. With the Polygon Tool still chosen, choose the Rotate Active Element Tool. Put the mouse pointer on the little red ball on the end of the X-Axis and holding the mouse button down, drag the pointer down and to the left of the Viewport, to rotate the Polygon about 45 degrees so that it faces partly up. Use the Extrude Tool again but this time set it's Offset to 200, and press Apply to get this (right image):

Don't ask me what it is! As an extra bit of excitement, with OSV ON, select the middle Polygon on the right face of the square part of the object and delete it (use the keyboard's normal Delete Key). A rounded hole appears. To make it more sharply rectangular, create two new Edges near its left and right ends, and then change to Perspective View and use the Viewport's Rotate Icon to confirm the hole in one side of the object. Now let's do some real modelling - the creation of an engineering part used in the animation of a steam engine - the top of one of the Crosshead Guides as shown in the image at the top of Page 1 of this tutorial.

SECTION 2: REAL MODELLING - A STEAM ENGINE PART
(Primitive Cage Method)

STAGE 1: MAIN BODY

This will become the object shown at the top of the first page of this tutorial. Create a Primitive Cube (Main Menu Bar > Objects > Primitive > Cube). In Front View, increase its X-dimension to 800 m. (To do that, select the Cube in the Object Manager, open the Coordinates Manager, choose the Model Tool and the Move Active Element Tool and drag the Cube’s right hand red dot until its X-dimension reaches about 800.) This will be the length of our object. Confirm that its Y and Z dimensions are each 200 m.)

Create a HyperNURBS Object (Main Menu Bar > Objects > NURBS > HyperNURBS) and make the Cube its child. Rename Cube as “Body” and make it Editable. In Front View, with Body selected, choose the Edge Tool. With SHIFT held down, use the Knife Tool (Main Menu Bar > Structure > Knife, or shortcut K) to “sharpen” the right hand end. The left image shows you using the Knife Tool and the right shows the results. (Adding Edges like this to sharpen is very common in HyperNURBS modelling.)

Then repeat with two more uses of the Knife Tool to sharpen the left and the bottom of Body. (The bottom is inevitably very slightly curved where the side meets the base, but I found that if I used Point Weighting, which produces a very flat base, there was a slight fault at the bottom four corners when rendered) :

NOTE: (If you do some experiments of your own extra to this tutorial, check from time-to-time that Body remains Selected in the Objects Manager.)

Next, we must raise the top surface in the middle. As a first step, change to Top View. With the Edge Tool chosen and using the Knife Tool again with SHIFT held down, create an Edge (from top to bottom in the Viewport across the width of Body at its middle) (not shown) . Using the Rectangle Selection Tool, (OSV ON), select the New Edge on the top of body. In Front View, Raise this Edge up a suitable amount: