Click here to go back to Part One of this article.

In Part 1, we have created a curve that is tangent to the edge of the existing surface. Now, we need to proceed to make the curve G2 (curvature) continuous to the edge.

We can use Match Curve to bring the curve to curvature (G2) continuity with the adjacent surface edge. Match Curve is within the Curve Tool panel. Select Continuity as Curvature from the Match Curve option. Note: For curves that have less than 6 control points, the curvature at the other end of the curve to match may be modified. The Preserve other end option prevents this modification.

From the screenshot shown above, we can see that the Curvature Graph displays a better flow with little or no sudden break or transition.

Next, we can bring up the Adjust Curve End Bulge tool to fine tune the curve. Make sure that the side (as indicated as 1 in the screenshot below) has Continuity = Curvature at the command line/prompt. For the other end (indicated as 2 in the screenshot below), in our case here, Continuity = Position is to be set. This is because we have only created enough control points for curvature to one end of the curve.

Once we are satisfied with this curve, we can proceed to create the other curve to match the other surface edge. Use the same method as described to ensure curve is curvature-matched to the edge as well. See illustration below of the other curve.

Now, we can use a surface tool with continuity to create the surface. In this case here, a new curve is created as shown below. The control point is turned on to adjust the profile to give it a slight bulge.

Next, using Surface from Network of curve, create the surface. Remember to set the Edge matching option to Curvature at the Options dialog. In this case, this is indicated as edge D. This is very important as surfaces do not automatically become curvature-matched even though the curves used to create them are.

Use the Zebra tool to evaluate the surface continuity.  Zebra strips can be used to indicate whether surfaces are position, tangent or curvature to each other. However, we are not going to go into the details here. Please note that the zebra tool cannot detect higher end continuity that can be seen by a curvature graph display.

What we have illustrated here is just a simple example. If we have additional adjacent surface edges to match to, the surface from network of curve tool can provide surface continuity matching options for all sides of its boundaries.

Well, that’s all for this article. Thanks for reading

About the Author: Being an industrial designer by profession, I have done much technical modelling projects for clients such as Razer and Creative Technology. I am proficient with Aliasstudio, Pro-Engineer and Rhinoceros 3D.

Disclaimer: We are in no way to be held responsible if the results is not as desired by you.

There are a few points to take note when creating adjacent surfaces with good level of continuity to each other. Traditionally,  position (G0) and tangent (G1) level continuity are not sufficient for smooth transition and can result in a noticeable break to the ‘flow’ of the form.

In order to maintain surface continuity with neighbouring (adjacent) surfaces, the curves to be used for surfacing MUST likewise attain the required continuity as well.
That is,

1. Construction curves must be tangent to each other in order for the corresponding surfaces to maintain tangency continuity.

2. Construction curves must be curvature to each other in order for the corresponding surfaces to maintain curves continuity.

It must be noted that in order to create a curve with a certain degree, the minimum number of control points required is ‘Degree + 1′. That means, a degree 3 curve will require a minimum of 4 control points. In Alias Studio, Control Points are call CVs. A good practice is to use the minimal amount of control points (CVs) to get the curve created. This is because we will want to minimise the necessary undulations that can result from excessive amount of manually-created control points.

Additionally, we can also investigate the continuity changes and dynamics along curves and surface. This can be done using the Curvature Graph. This is as shown below.

To build adjacent curvature curves, one method that I use is to

1. first build a curve that is tangent to the adjacent curve.

2. Use Match tools to rematch the curve to G2 continuity

3. Fine tune the curve with a combination of Curvature Graph and End Bulge command.

To build a tangent curve, I turn on the Control Point Display of the surface to be tangent to. (As shown below)

Next, I start to create the curve using the Control Point Curve.

First, use the point or end osnap to snap the first control point of the curve to the end of the edge. Next, making sure that the Point Osnap is enabled, snap (but do not click) the next point to the next control point of the existing surface edge. This is as shown below.

The directional lock is now activated. Move the cursor to the opposite end to start clicking to create the curve. As we want to create a curvature-level curve, the minimum number of control points (CVs) required is 4 (ie, 3 +1).

Additionally, if we are creating the curve correctly, the 2nd control points of the surface edge and the newly create curve as well as the 1st point of the curve should form a straight line. This is as illustrated below.

Now, turn on the Curvature Graph for the edge as well as the newly created curve. For this illustration purpose, the edge curve is used to display the curvature graph instead of the surface itself. This is as shown below.

As you can see, the Curvature graph shows that the flow is not continuous and smooth. The break indicates that the match between the edge and the newly created curve is not G2.

This is the end of part one of the article.

>>> Click here to go to part 2 of surface continuity article.

Disclaimer: We are in no way to be held responsible if the results is not as desired by you.

>>> Click here to go back to Part 1.

Now, we need to point to the location of the texture map that was created and exported from Sculptris. Click the ‘Open’ button to locate and load the texture. This is as shown below.

Now, the texture should be loaded. Next, we need to tell Blender the coordinate type of the texture. Under Mapping >>> Coordinates, select ‘UV’. This is as shown below.

Besides indicating the mapping coordinates, we also need to indicate to Blender what influence the map is to be used for. Since the map is a colour map, under ‘Influence’, check ‘Colour’. You can also  use the map for more than one type of influences. For bump maps, click ‘Normal’.

If you render the scene now, the model should have texture now.

Thanks for reading the tutorial. Drop me a comment if you have any queries

In case you do not know what is Sculptris, it is a very cool (and yet free) 3D sculpting program that works similarly to programs such as  Mudbox and Zbrush. Sculptris is highly intuitive to use and allows a newcomer to easily create complex organic models without much training.

After you are done with the modeling and painting within Sculptris, export the texture map. Next, export your model as a Wavefront OBJ file either by clicking the export OBJ button or pressing the CTRL and E-keys.

In Blender, import the model as Wavefront OBJ format as illustrated below.

The model should come in nicely. However, we will need to assign the texture map correctly onto the model.

With the model selected, go to the Texture panel. In case, you don’t know where the texture panel is, it is accessed by clicking on the checker-patterned square icon.

Click the ‘+’ symbol to add a new texture. For texture type, select ‘Image or Movie’. This is as shown below.

>>> Click here to go to Part 2 of this tutorial.

>> Click here to go back to part one.

In the previous part, we have already created the twist as shown below.

Now, create the curve that the twist tubes will have to conform to. This newly created curve is as indicated by the red arrow as shown below.

Here, we are going to use the Flow along curve command.

Objects to flow along curve are the tubes. Base curve is the first straight line that we have created. Make sure that the curve is selected at the intended end. For target curve, select the newly created curve. Set the Stretch option to Yes.

The final result should be similar to what is being shown below.

That’s all for this tutorial. Hope that it is of use to you