Tutorial 2 - Curves and Curve Based Object Creation

Tutorial 2 - Curves and Curve Based Object Creation
This tutorial presumes that you have a basic understanding of "4D Blue" functions, especially that you know how to move, adjust and rename objects. In this tutorial, we will start from the scratch. Using curves, we will create some interesting objects. It will show you how to create new curves, manipulate them, and then how to use one or more of them to create new surfaces.
Step 1 - Creating new simple curve.
	Start with a new scene. In the context menu, select "Curves" and then "NURBS Curve". In "4D Blue", all curves are NURBS curves as they offer the greatest flexibility, and naturally can be used to create NURBS surfaces if needed.
	Select the newly created curve and rename it to "Curve 1". With the curve being selected, start "Curves Editor" which is the 5th toolbar. In "4D Blue", a "curves resource" can contain more than one curve, although just one curve is enough in most situations. However, more than one curve is sometimes necessary, especially when creating objects that are supposed to be hollow inside like text objects.
	When you switched to "Curves Editor", you probably have already noticed that the top toolbar has expanded with new tools. Quickly familiarize yourself with their names.
	Using "Add Points" tool, add points in the "Z-Y Side" view until you get a curve like the one on the left.
	You have probably noticed that the curve is not very well aligned to the grid. We are going to change that now. Switch to "Local" (L) coordinate system and select "Snap to Subdivided Grid" option.
	Using the "Move" tool to adjust the points to the grid, the final curve should look somewhat like the one on the left.
	The curve is still open on the top, since we need a closed curve, we need to change the knot vector type to "Closed".
	And eventually we can smooth the curve by increasing its degree to 3 (cubic).
	Switching back again to "Nodes Toolbar", we can see our ready new curve.
Step 2 - Creating a bevel object.
	Have the curve selected, open the context menu, select "Polygonal Objects" and then "Bevel". A new bevel object based on the curve will be created.
	As we can see in the side view, the object is not very smooth. We are going to adjust that right now.
	In the object's constructor, set the "Parameterization" to "Edit Points" and enter 4 in the field "In-Between Samples". That should smooth the surface quite a bit. Parameterization controls how the curve is sampled when creating surfaces.
	It is difficult to see how the new surface looks like using just the top-front-side views. We are now going to learn how to use a new view type called "Ortho-Ball". In the lower right view using context menu, select "Select View Type" and then "Ortho-Ball". Set also the shading to "Gouraud" and disable specular highlights.
	Using the "Alt" key, mouse adjust the view until it looks like the image on the left.
	Now that we can clearly see the surface, we are going to make final adjustments. Adjust the surface creation parameters to the one on the left image.
	The final surface should look like the one on the left.
	We no longer need our object, and we don't want it to clutter the views. We could either start new scene or delete the object and the curve. But we are going to do something different. We are going to hide them. With the object selected in the "Nodes Toolbar", bring the tree context menu with right mouse button and select "Parameters".
	In the dialog box that has been down in the "Display Parameters" section, select "Don't Display (Hide)". The object is still there, except we can no longer see it in the views. We can always show it again later if we need to. Hide the curve the same way as well.
Step 3 - The "Cup" - Creating a lathe object.
	Create a new curve and name it "Curve Cup". Using the same method as in step 1, create the following curve like the one on the left. The curve doesn't have to be exact, something similar or looking like a cup when lathed.
	Go back to "Nodes Toolbar", have the curve selected and create a "Lathe" object based on it.
	A surface like the one on the left should be created. We can see that the normals look flipped, since we can see the inside of the cup.
	In the object's constructor, set the "Flip Normals" flag. The normals of a surface are based on the curve shape. Usually 50% of the time, they are incorrect and need to be adjusted. Always look for incorrect normals when working with curves.
	Now that the shape looks ok, we can make some final adjustments to it. Set the "Parameterization" method to "Edit Points", and set the "In-Between Samples" to 4. Also adjust the sweep segments to around 48.
	The final surface should look like the one on the left. As we are done with the object and the curve, we can hide them.
Step 4 - Creating a plane object.
	Create new curve and rename it to "Plane". Go to "Curves Editor", and in "Curve Creator", choose "Gear Wheel Constructor".
	Keep the default settings; they are ok for our purposes. Press "Create".
	A gear wheel curve is created. But the first thing we notice is that the shape is bit edgy. But NURBS curves can't be edgy, so there must be problem with our preview sampling resolution. Let's see if we can fix that.
	Still in the "Curves Editor" at the bottom in the "Display" section, we are going to select "High Quality" and "Knots" for selected curves to reduce the amount of visual clutter.
	The curve look so much clearer now. We could adjust it more, but we are ready with it for this tutorial.
	Go back to "Nodes Toolbar" and select the new curve. Create new "Planar" Object. You might need to flip the normals in the constructor if the surface is not shown in the views.
	In the surface constructor in the "Parameterization" section switch to "Edit Points", and adjust the "In-Between Samples" until the surface looks accurate enough.
	The final surface should look like the one the left. We are done with it and you can delete or hide it.
Step 5 - The "4D" - Creating a "Cookie Cutter" Object.
	Create a new curve and rename it "4D". In the "Curves Editor", choose "Text Constructor" from "Curve Constructor". Enter "4D" as the text and set the tilt to 10 degree. Click Create. The text curve is ok and we are done with it. Go back to "Nodes Toolbar".
	The new curve should look like the one on the left. Select it and create a new "Cookie-Cutter" polygonal object. Rename it to "4D".
	The new object clearly doesn't look right, but we are going to make it look all right in no time with few adjustments!
	First in the object constructor, we adjust the parameterization to "Edit Points" and 2 in-between samples.
	The normal vectors are not right. By experimentations, we conclude that we need to flip all normals. Set both flip normals flag and deselect "Weld Seams" flag. Set "Cap Edges" to "Convex" and adjust the bevel parameters as shown on the left image. As you adjust them, try different values and see how they affect the final shape of the object. This way you will get a feel on all the parameters that affect the surface.
	The final object should look like the image on the left. You can hide the "4D" object now as we are done with it.
Step 6 - "Spring" - Creating an extruded object based on two curves.
	Create new curve object. Rename it "Circle". Use "Curve Constructor" to create a circle with radius of 0.1
	Create new curve object. Rename it "Spiral". Use "Spiral Constructor" to create a spiral with 20 segments, radius of 1.0, degree span of 720, and height of 2.0
	The new curves should look like the image on the left.
	Create new polygonal "Extrude" object. In the object constructor set the style to "Path Curve - Tangent". Use the "Circle" as profile curve and the "Spiral" as a path curve. Extrude tool can also work with single profile curve without a path curve. In such situations you would use "Distance Path" and would need to specify how long you want the extruded surface to be.
	Set the "Always Use Center Pivot" flag. This will force the surface constructor to compute the profile curve center point and use it as a starting point for the path curve.
	The surface already looks better, but we still need to adjust the quality setting to be completely done. Set them to the same values as seen on the left image.
	The final surface should look like the one on the left. You can hide it now.
Step 7 - Lofting an object from curves.
	Create a new curve and name it "Loft 1". Create a curve like the one on the left. Increase its degree to 3 when done.
	In the "Nodes Toolbar", copy the new "Loft 1" curve and rename it to "Loft 2".
	Switch "Curves Editor" and using the "Move" tool, adjust the control points on the copied curve to look like the one on the left image.
	Again copy "Loft 1" curve and rename it to "Loft 3". Again using "Curves Editor", adjust the "Loft 3" curve to look like the one on the left image.
	Copy the "Loft 1" curve one more time and rename the new curve "Loft 4". This time, you don't need to adjust it. The curves should look like the ones on the left. Move the curves in the Y direction as follow: "Loft 1" by 2.0, "Loft 2" by 1.5, "Loft 3" by 1.0, and "Loft 4" by 0.5.
	Create new polygonal "Loft" object. Enter the 4 curves in order and adjust the other parameters as shown on the left image. Based on the curve direction, you may or may not to flip the normals.
	The final surface should look like the one on the left image. Keep the object and the curves as we will use them in the next step.
Step 8 - Creating a birail object.
	Birail works almost like the "loft" tool, with the addition that you can also specify two rail curves on which the "loft" curves "ride". Once again, create a new curve and rename it to "Rail 1". Using "Curves Editor", create a curve like the one on the left and then increase its degree to 3.
	Copy the "Rail 1" curve and rename the new curve to "Rail 2". Rotate the "Rail 2" curve by -180.0 degrees in the Y axis. The final curves should look like the ones on the left image.
	Create new polygonal "Birail" object. Setup its construction parameters just like shown on the left image. Also set the "Smooth" flag at the bottom. The value specifies the loft curve positions, 0.0 is the beginning of the rail curve and 1.0 is the end of the rail curve. The rail curves should both point in the same direction.
	The final surface should look like the one on the left image. Birail is clearly a very powerful tool in the skilled hands. This is the last step in this tutorial. I clearly could not cover every single construction parameter or give examples of all the possible surfaces that can be created using curves. But I hope that I gave you enough information to start trying different values and different curves and see what you can do with them. These tools can be very powerful if used correctly. The NURBS constructors work almost exactly like the polygonal ones, although they might be bit slower on complex surfaces.
Step 9 - Rendering the created objects (Optional).
	Using the skills from the previous tutorial, create new materials for every object and compose a complete scene with the objects we just created and render them.

Tutorial 2 - Curves and Curve Based Object Creation

Step 1 - Creating new simple curve.

Start with a new scene. In the context menu, select "Curves" and then "NURBS Curve". In "4D Blue", all curves are NURBS curves as they offer the greatest flexibility, and naturally can be used to create NURBS surfaces if needed.

When you switched to "Curves Editor", you probably have already noticed that the top toolbar has expanded with new tools. Quickly familiarize yourself with their names.

Using "Add Points" tool, add points in the "Z-Y Side" view until you get a curve like the one on the left.

You have probably noticed that the curve is not very well aligned to the grid. We are going to change that now. Switch to "Local" (L) coordinate system and select "Snap to Subdivided Grid" option.

Using the "Move" tool to adjust the points to the grid, the final curve should look somewhat like the one on the left.

The curve is still open on the top, since we need a closed curve, we need to change the knot vector type to "Closed".

And eventually we can smooth the curve by increasing its degree to 3 (cubic).

Switching back again to "Nodes Toolbar", we can see our ready new curve.

Step 2 - Creating a bevel object.

Have the curve selected, open the context menu, select "Polygonal Objects" and then "Bevel". A new bevel object based on the curve will be created.

As we can see in the side view, the object is not very smooth. We are going to adjust that right now.

In the object's constructor, set the "Parameterization" to "Edit Points" and enter 4 in the field "In-Between Samples". That should smooth the surface quite a bit. Parameterization controls how the curve is sampled when creating surfaces.

Using the "Alt" key, mouse adjust the view until it looks like the image on the left.

Now that we can clearly see the surface, we are going to make final adjustments. Adjust the surface creation parameters to the one on the left image.

The final surface should look like the one on the left.

In the dialog box that has been down in the "Display Parameters" section, select "Don't Display (Hide)". The object is still there, except we can no longer see it in the views. We can always show it again later if we need to. Hide the curve the same way as well.

Step 3 - The "Cup" - Creating a lathe object.

Create a new curve and name it "Curve Cup". Using the same method as in step 1, create the following curve like the one on the left. The curve doesn't have to be exact, something similar or looking like a cup when lathed.

Go back to "Nodes Toolbar", have the curve selected and create a "Lathe" object based on it.

A surface like the one on the left should be created. We can see that the normals look flipped, since we can see the inside of the cup.

In the object's constructor, set the "Flip Normals" flag. The normals of a surface are based on the curve shape. Usually 50% of the time, they are incorrect and need to be adjusted. Always look for incorrect normals when working with curves.

Now that the shape looks ok, we can make some final adjustments to it. Set the "Parameterization" method to "Edit Points", and set the "In-Between Samples" to 4. Also adjust the sweep segments to around 48.

The final surface should look like the one on the left. As we are done with the object and the curve, we can hide them.

Step 4 - Creating a plane object.

Create new curve and rename it to "Plane". Go to "Curves Editor", and in "Curve Creator", choose "Gear Wheel Constructor".

Keep the default settings; they are ok for our purposes. Press "Create".

A gear wheel curve is created. But the first thing we notice is that the shape is bit edgy. But NURBS curves can't be edgy, so there must be problem with our preview sampling resolution. Let's see if we can fix that.

Still in the "Curves Editor" at the bottom in the "Display" section, we are going to select "High Quality" and "Knots" for selected curves to reduce the amount of visual clutter.

The curve look so much clearer now. We could adjust it more, but we are ready with it for this tutorial.

Go back to "Nodes Toolbar" and select the new curve. Create new "Planar" Object. You might need to flip the normals in the constructor if the surface is not shown in the views.

In the surface constructor in the "Parameterization" section switch to "Edit Points", and adjust the "In-Between Samples" until the surface looks accurate enough.

The final surface should look like the one the left. We are done with it and you can delete or hide it.

Step 5 - The "4D" - Creating a "Cookie Cutter" Object.

Create a new curve and rename it "4D". In the "Curves Editor", choose "Text Constructor" from "Curve Constructor". Enter "4D" as the text and set the tilt to 10 degree. Click Create. The text curve is ok and we are done with it. Go back to "Nodes Toolbar".

The new curve should look like the one on the left. Select it and create a new "Cookie-Cutter" polygonal object. Rename it to "4D".

The new object clearly doesn't look right, but we are going to make it look all right in no time with few adjustments!

First in the object constructor, we adjust the parameterization to "Edit Points" and 2 in-between samples.

The final object should look like the image on the left. You can hide the "4D" object now as we are done with it.

Step 6 - "Spring" - Creating an extruded object based on two curves.

Create new curve object. Rename it "Circle". Use "Curve Constructor" to create a circle with radius of 0.1

Create new curve object. Rename it "Spiral". Use "Spiral Constructor" to create a spiral with 20 segments, radius of 1.0, degree span of 720, and height of 2.0

The new curves should look like the image on the left.

Set the "Always Use Center Pivot" flag. This will force the surface constructor to compute the profile curve center point and use it as a starting point for the path curve.

The surface already looks better, but we still need to adjust the quality setting to be completely done. Set them to the same values as seen on the left image.

The final surface should look like the one on the left. You can hide it now.

Step 7 - Lofting an object from curves.

Create a new curve and name it "Loft 1". Create a curve like the one on the left. Increase its degree to 3 when done.

In the "Nodes Toolbar", copy the new "Loft 1" curve and rename it to "Loft 2".

Switch "Curves Editor" and using the "Move" tool, adjust the control points on the copied curve to look like the one on the left image.

Again copy "Loft 1" curve and rename it to "Loft 3". Again using "Curves Editor", adjust the "Loft 3" curve to look like the one on the left image.

Copy the "Loft 1" curve one more time and rename the new curve "Loft 4". This time, you don't need to adjust it. The curves should look like the ones on the left. Move the curves in the Y direction as follow: "Loft 1" by 2.0, "Loft 2" by 1.5, "Loft 3" by 1.0, and "Loft 4" by 0.5.

Create new polygonal "Loft" object. Enter the 4 curves in order and adjust the other parameters as shown on the left image. Based on the curve direction, you may or may not to flip the normals.

The final surface should look like the one on the left image. Keep the object and the curves as we will use them in the next step.

Step 8 - Creating a birail object.

Birail works almost like the "loft" tool, with the addition that you can also specify two rail curves on which the "loft" curves "ride". Once again, create a new curve and rename it to "Rail 1". Using "Curves Editor", create a curve like the one on the left and then increase its degree to 3.

Copy the "Rail 1" curve and rename the new curve to "Rail 2". Rotate the "Rail 2" curve by -180.0 degrees in the Y axis. The final curves should look like the ones on the left image.

Step 9 - Rendering the created objects (Optional).

Using the skills from the previous tutorial, create new materials for every object and compose a complete scene with the objects we just created and render them.