Final model

STEP 1

First things first. Make sure you got your Snap option turned on in the status bar, and your OSnap enabled with some of the most commonly used options like End, Near, Point, Mid and Int.

We’ll start creating this little shovel from top viewport, like we would start tracing an image of some existing shovel imported in Rhinoceros.

With Curve command, create a curve in Top viewport which has its control points exactly like on the image below. This is why Snap (to grid) is handy tool to use here.

Image 1

Then we need another copy of this curve, and for that we will use Mirror command and mirror it across x axis.After that, use Join command to join two curves.

Then we can either use Line command to close these two curves into one closed polyline/polycurve, or use Close command which will do the same thing with less clicks.

Image 2

Now, using Rectangle command we will create a rectangle like on the image below: do not worry about the dimensions, just count the grid boxes and you’ll be fine. I’ve got some dimensions for you in case you get lost

Image 3

With Trim command, we will trim the parts of the two closed polylines which will help us join all curves into one closed:

Image 4

Next thing would be to make the corners smoother. They aren’t normally that sharp, are they? So, using Fillet command we need to fillet the upper and lower corners with 1 unit, and the inner ones with 2 units, and the tip of the shovel with 0.4 units:

Image 5

Now, before we go any further, it is good to check if all these lines and curves are joined all together. Just click anywhere on the line, and if everything is ok then it will be yellow as selected. One more thing to check is if this IS really closed curve with SelClosedCrv command which will select all closed curves.

Next thing we need is a basic shape of our shovel. Since it is curved in two sides, the best basic shape would be an ellipsoid. Using Ellipsoid command create one positioned just like on the image below:

Image 6

Ok, now we will Cut the Ellipsoid with the closed curve we created. From Top viewport, we need to select both Ellipsoid and closed curve, and run Project command. It is important to do this in Front viewport because the viewport is controlling the direction of the projection.

Image 7

Now we got two projected curves. One on the top and one on the bottom of ellipsoid. We don’t need the upper one, and we can delete it by selecting it and hitting Delete key on keyboard.

Using Split command, we will first select the object we want to cut which is in this case ellipsoid, and then the curve which is the object we wish to split with:

Image 8

Now we have finally created something that is actually resembling our shovel. This is one thin surface, and we need some thickness. Using OffsetSrf command we will first offset the surface and create one on top with distance of 0.3 units: (when you start the command, it will display white arrows on your surface, those are normals, and are used to see in which direction the offset will occur. Chances are your arrows point towards bottom, click on the surface and the arrows will change direction)

Image 9

We now have two flat surfaces and we need to connect them somehow. We’ll do that with BlendSrf command which will basically create nice blend surface between two surfaces: (Use AutoConnect option in command line)

Image 10

With Join command join the blend surface with two flat surfaces. You will notice on the part where would handle start there is some weird hole. Never mind that, that part will soon disappear.

Again, we need to create another Ellipsoid. Using Ellipsoid command create one like on the image below. Again, the positioning and size is crucial here.

Image 11

Hint: When you start Ellipsoid command, just follow these steps. Input “10, -3.75″ (that will set the center in the right position), press enter while active Front viewport (click anywhere in the viewport), “6, -3.75″ (that will set one dimension of the ellipsoid – length), press enter while still in Front viewport, “10, -2.25″, press enter while in Front viewport, “10,-1.5″ press enter Top viewport is active. Do not input apostrophe signs.

Using ExtractIsoCurve command, create a extract isocurve from the middle of ellipsoid. You need to hit the Quad point to make sure the circle is in ellipsoid’s center.

Image 12

Using ExtrudeCrv command we will create a cylinder out of this circle. So, start the command, select the circle, make sure the Cap option is set to Yes, and input 15 units in command line as extrusion distance.

Image 13

With BooleanUnion command connect ellipsoid with cylinder:

Image 14

Again, with BooleanUnion command we need to connect the plate and handle part:

Image 15

If you are getting something like on the image below….

Image 16

… then you need to use Dir command on the plate before you use BooleanUnion. Because the normals are pointing towards the inside, while they should point towards outside.

This next part will be a bit tricky, so pay attention. We need to create a variable fillet on the edges that connect the handle part and the shovel plate. The biggest radius will be 1 unit, while all others will be 0.8 units.

So, start FilletEdge command, and set 0.08 as default radius. Select the edges:

Image 17

… press enter, and click on AddHandle option in command line. Add 7 more handles like on the image below:

Image 18

The two big ones show be set to 1 unit, and you do that by clicking on the outer dot (center of an arc) and inputing the values.

Image 19

Final rendered model of our windup clock

When approaching modeling this clock, and any other model, I first try to divide it into parts. Obviously every product has its parts, and naturally you would go model one by one. This is that kind of model where your don’t have to think about which part to model first. This is obvious, first you need a clock body, then you can go about modeling which ever part. Here I first created the body, then the back plate with screws, then the front plate without numbers, bells and hammer, legs, and then in the end made the numbers and handles for the front plate.

STEP 1

Ok, in this step we will be creating the body. Since I lost every clock I had like this, I had to model it from reference images from the internet. So, we don’t have the measures, or technical drawings, but we need to model by eye, looking at the various images and approximate the lengths, distances and so on.

I created a template for my default usage with grid extents set to 10. So, make sure you do the same with Snap command, and clicking on the Extents options and input 10.

Now, we can start modeling. Since we don’t know what the accurate dimensions are, we will need to use our old method of trial and error. We will first create three straight lines with Polyline or Line command.

img1

Next thing would be to connect these lines with curves, and that we will do with BlendCrv command. Make sure you use G1 for both ends, so we get tangency.

img2

Using Join command make sure those lines are all joined together. So, next thing would be to create a surface out of this section curve, and we’ll do that with Revolve command. But, before that, we need to turn on the Record History option, so we can work on the surface by simply editing the curve.

img3

Now, if we select our initial curve, and using PointsOn command turn on the control points and if we move those points, we will automatically update the surface as well. If we used Record History that is.

img4

Ok, next thing would be to adjust the curves a bit so the surface is little more accurate. Try to make something like on the image below:

img5

Using OffsetSrf command, we need to offset this surface to inside by 0.3 units. So, make sure you flip the direction normals when in OffsetSrf command, so they point to inside.

img6

Then, simply, with BlendSrf command blend the gaps and Join the four surfaces.

img7

You can download this tutorial in PDF format here.

Organic Modeling for Jewelry Design with T-Splines and Rhino® 4

Designing an Earring

Juan Santocono

Industrial Design

Universidad de Buenos Aires, Argentine

Matt Sederberg

T-Splines, Inc.

© Copyright 2008 T-Splines, Inc.

Designing freeform objects can be difficult when working with traditional CAD software. T-Splines and Rhino 4 offer an easy way to create smooth, gap-free freeform models for jewelry design.

The best way to read this tutorial about how to model a earring using T-Splines is by look­ing at the 3D model at the same time. You can follow the model’s progress by selecting the differents layers in the file. T-Splines for Rhino must also be installed on your computer. Both T-Splines for Rhino and the earring model can be downloaded at www.tsplines.com.

In this tutorial, anything in Blue is a Rhino command, while anything in Red is a T-Splines command. Type these commands in the command line of Rhino to run them.

STEP 1 – MESH

Creating the base mesh
To get the general shape of the ear­ring we will start by creating a Mesh­torus, with VerticalFaces=8 and AroundFaces=16.

STEP 2 – T-SPLINE SURFACE

Converting the mesh
Once we have the mesh torus we just need to convert it to a T-Spline surface.

Use tsConvert and select the mesh to perform the conversion. Now we have a T-Spline torus with the same control points as the mesh torus.

STEP 3 – T-SPLINE MODIFICATION

Extruding faces
The earring design is a sun, so we need to create the sun rays. We will include some long rays and some short rays.

We will create the long rays first. To make these, we will extrude some faces with tsExtrude.

1-Extrude selected faces (yellow) as shown.

2-In order to get flat rows of control points for the next extrusions, we need to flatten selected points. Use tsScriptFlattenPoints. Do this with each of the 4 ray tips separately.

3-Extrude the flattened faces again (tsExtrude).

4-Extrude them again.

5-Extrude them twice more (a total of four extru­sions). This will give us sufficient control points to add details to the rays.

STEP 4 – T-SPLINES ADJUSTMENTS

1-Draw the base and target curves for both sides of the sun rays.

2-Use FlowAlongCurve on all the left-side control points.

3-Use FlowAlongCurve on all the right-side control points.

STEP 5 – T-SPLINES ADJUSTMENTS

Modifying front profile
To modify the front profile we are going to do something similar to the previous step, but (for the sake of introducing an alternative workflow) instead of using the flow command we are going to do it manually. Draw some reference curves to provide us with a reference on how we will to transform the surface.

1-Once we have the reference curves, just select the lower row of control points (shown) and use tsManip (scale and move) to match the surface profile to the curves.

2-Repeat this process with the four rows of control points. This manual method can give us a decently accu­rate surface.

3-Now we have the shape that we want on one sun ray.

STEP 6 – T-SPLINES ADJUSTMENTS

Modifying details
Now we need to do some further adjustments to get the desired design. First, use tsManip to scale (+Y) all the center ray control points, this is to give a concave curvature to the sun rays.

Remember to select all the center points of the four rows on each side.

Second, using again de tsManip scale this four tip point, this will give us a more smooth tip.

1-Scale center control points +Y.

2-Scale tip control points -X.

STEP 7 – T-SPLINE ADJUSTMENTS

Copying the rays
We have completed the shape of one sun ray, now we need to shape the others. The design intent is that all four rays should have the same form, so we need to copy our first sun ray shape to the other three rays. Doing this manually would be slow and imperfect. For this rea­son we will use a method that assures us of the exact same shape on all the rays.

1-Select all control points of the shaped ray.

2-Use ExtractPt to make a point from each con­trol point.

3-Draw a Polyline, snapping to each row of po­ints. This represents the control polygon of the ray surface. Connecting the points is not strictly necessary, but is useful to give a visual unders­tanding of the control polygon.

4-Groups of control points from the shaped ray.
5-Copy these control polygons to each ray. Use Rotate (copy on).

6-Now, using snap (points and ends) move each T-Spline control point on each ray to its corresponding control polygon point from the shaped ray.

7-Repeat this with each ray until all four are shaped.

This method of copying shapes by snapping to copied control points might seem a little tricky at first sight, but with re­latively simple T-Splines shapes it is really fast and insures a symmetric shape.

STEP 8 – T-SPLINE MODIFICATION

Extruding small rays
Now we are going to create the shorter rays. For this we will extrude some faces with the tsExtrude command.

All of the modeling steps used to create the shorter rays are similar to those used for the lon­ger rays. Just follow the same workflow.

1-tsExtrude selected faces.

2-Flatten each face’s control po­ints (tsScriptFlattenPoints).

3-tsExtrude the flattened faces.

4-tsExtrude again and again. Four times total, just like the longer rays

STEP 9 – T-SPLINES ADJUSTMENTS

Copying smaller ray shape
Here we are going to use the same method we used on the longer rays, but we’ll save time by just copying and scaling the control polygons used for the longer rays and reusing them for the smaller rays. Just copy the control polygons of the longer rays, rotate them by 45 degrees, and scale them to be smaller. This will allow all rays, both long and short, to have the same shape.

STEP 10 – T-SPLINES ADJUSTMENTS

Modifying the center ring
To get the correct design we need to do some adjustments on the center hole. The intention is to have a bigger hole and a sharper edge on the transition betwen the sun body and the sun rays.

1-Select the control points shown and using scale2D, scale them outwards to give the hole a wider diameter and smooth the inner torus curvature. (The origin of the 2D scale is the center (0,0,0).)

2-Select the control points shown and using scale2D, scale them outwards to create a shar­per edge between the sun body and the sun rays.

STEP 11 – T-SPLINE ADJUSTMENTS

Adding control points
We need to add some more control points using tsInsertPoint for the next step. Adding a con­trol point near a star point (shown) will yield a small explosion of new control points to keep the surface unchanged; this influx of control points is desired in this case.

One more tweak before the next step: we’ll adjust the sun rays pro­portions. Just select the last 3 rows of the big rays and scale2D throught the center:

STEP 12

Creating a crease
Until now we have created a perfectly smooth T-Spline surface, but the design intention is to have a sharp edge on the inner part of the rays. Use tsCrease and select the first segments of each ray (both sides). The crease influence will extend across two isoparms.

STEP 12

Creating the body details
Basically, what we are going to do on this step is generating some strips that will decorate the body.

1-tsExtrude these front faces as shown.

2-Once they are extru­ded, we need to change the angle of the control points on these faces. A good way to do this on all faces at once is to scale2D on the selected points shown.

3-Now that we corrected the faces, it’s time for another tsExtrude.

4-Keep the extruded points selected and use the tsManip to move +Y to get a con­vex body.

5-Now it is time for one last tsExtrude.

6-We need to scale2D these control points that were extruded last, this will give us smaller and closer tips. The center of the scale should be on the center of the earring in order to modify it symmetrically.

7-Now, we want the strips to be deformed in a spiral. To make the deformation more accu­rate, we first need to add more control points. To do this, just use tsInsertPoint near the star point shown. This will generate the needed geometry for the deformation.

8-To make the spiral deformation we will use Maelstrom, one of the UDT tools. First, select all the control points that comprise the sun body strips. Be careful to not select other points.

Second, use the maelstrom tool, where the center is the middle of the earring and the first and second radius are just those necesary for rotating the control points.

The T-Spline surface is done! Now we only need to add the remaining details.

STEP 14 – OTHER PARTS

Creating the center part
For the center piece we will just create the profile of a shape and then use Revolve to gener­ate the geometry. You can use ExtractIsoCurve on the T-Spline surface to extract the curves that will be used for the center piece profile to get a perfect match between the parts.

Creating the hook
This is simple, draw the curve and use Pipe to generate the piece.

Union part
Draw the curve and use Pipe to generate the piece. Then just use BooleanDifference (Delete input=No) with the T-Splines surface.

Move the parts to fit each other.

The result is a perfectly smooth, highly detailed 3D model of an earring ready to be manufac­tured.

Good luck in your modeling!

Write to my e-mail below with any questions.

Juan Santocono,

Industrial Design

jsantocono@fibertel.com.ar

A free trial of T-Splines for Rhino may be downloaded at www.tsplines.com