Tutorials

Or idea was to come up with reproduction methods that would be able to apply to every possible cup, plate etc. To test this we all took a different scanned object and made a small tutorial on how apply the reproduction technique.

1) Plaster print + transparent holes with Ginny

In the first picture is show how the Ginny is imported in Rhino, ‘freshly’ from Avizo. There is one hole that needs to be filled and two bricks that can be ‘re-cracked’.
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Firstly, the hole shall be fixed. In order to do this, a sketch is made along a section near the hole that covers the hole roughly. A view is chosen in which the side of the hole can be viewed best. This sketch is then oriented to the middle of the hole and tangent to the round shape. Then, a revolve is executed. The result can be seen below. You can see that the revolve exceeds in some parts. It can be oriented just so that it does not exceed anymore.

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Now, because Ginny is a mesh, we shall use Mesh > Mesh Boolean > Difference to create the new shard. Some loose pieces will emerge. These are difficult to remove because they are a part of the mesh. Exploding the mesh will disconnect every triangle from the mesh. Therefore it is recommended not to let any parts exceed from your revolve.
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Next up is the ‘re-bricking’ of Ginny. The easiest way to do this, is to choose a view in which the brick is best visible and drawing a curve over it. In this case the top-view. Then, the curves can be extruded and split with Mesh>Mesh Boolean>Boolean Split. After this, the bricks can be laid down, oriented in the best way to print them.
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2) CNC milling and Vacuum forming Ron

To be able to vacuum form a cup you need to make a mold. This can be done with the cnc machine, but first the file needs to be adjusted with a few simple steps:

1) Determine in which direction you’re going to vacuum form. With a cup you want the outside so the mold will be a cup upside down, but a plate would be formed in the normal direction.
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2) Make sure the cup is standing horizontal, this is important for the last step. If the object contains loose pieces, then place them where you think they should be.
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3) Make a sketch to fill the open holes, since the inside of the cup is not important this doesn’t need  to be finished neatly.
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4) Revole the sketch full circle. Afterwards check in perspective mode if the shape stays inside the cup, if not you need to move the the shape or sometimes even resize it.
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5) Place a bottom plate underneath the shape and then the mold is finished.
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After making the mold the only thing left is the vacuum forming process. Depending on the desired firmness you can choice between 1 or 2 mm thickness and between a white or transparent color.

3) Making a multi- material object
Since Harmione has a big hole first the cup needed to be fixed. A line was drawn and using ‘Curve Extrude’ an extrusion was made. With ‘Mesh Boolean Split’ the part separated from the cup and was able to be duplicated and mirrored. Using ‘Mesh Boolean Difference’ The shape below is left  over. This is the part that fits exactly in the big hole of Hermione.

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The next thing to do was to make the cracks of Hermione more visible. Again a line was drawn and ‘Curve Extrude’ was used to make a separation in the cup. Only this time two surfaces were created so the crack was separated from the other parts of the cup. Because of the cracks that are not straight through the ceramic the points of the surfaces needed to be dragged so the surfaces surrounds the cracks well. 

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When this is done the cracks and the new sharf can be saved as one part and the separated sharfs can be saved as one part in an .STL file. The connex printer is able to print these to files at once in two different materials.

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4) creating a inner structure

Before beginning, you should have all the holes filled in the object: full tutorial below. First step is to duplicate the whole mesh into another layer and trim it precisely in the middle.

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Secondly, you should open the side view and sketch the average line between the walls, going till the middle of the object.
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Afterwards use revolve command with the axis going from the bottom, middle point straight up. Cap2

This surface is then loaded into Grasshopper for further paneling (e.g. with Grasshopper plugin Lunchbox). The thickness of the line can either be given by the command  Pipe or Exoskeleton. The latter is another plugin for Rhino and makes the joints run smoother.grasshopperAnother way to make surface patterns is making your own geometry in Rhino and then repeating it while it follows the surface. A quick tutorial for this can be found on YouTube.grasshopper1

After baking the surface it should look approximately like this:cap3

For the finalizing, you should have a bottom shard, on which the cup stands, and the top brim split from the main mesh. They should go into the same layer as the inner structure created in Grasshopper, while the rest of the mesh should be assigned a transparent material.
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Tutorial: How to fill a hole

Hereby a step by step tutorial about remake missing pieces of broken ceramic objects in Rhinoceros. Due to calculating limitations from our laptops, it was impossible to turn the mesh-objects into polysurfaces. Also, that process would affec
t the detailing a lot.

For this instance, we want to fix the following hole:

Harry hole to fix

  1. Create a polysurface that flows ‘through’ the cup and hole.
    • Create sketches along a section of the cup. You can do this by choosing a side view and setting the view to ‘Wireframe’. This way, a section from that view will be visible through all the wires.
    • For smaller holes, one sketch + revolve around the origin will suffice. Since this hole is bigger, I made two sketches and two rails in order to perform a ‘Sweep 2 Rail’.Harry big hole sketch
  2. Ready the shape for MeshBooleanDifferance
    • Give the new shape an other color to see where it exceeds the hole.
    • Roughly cut the exceeding part out using surfaces and BooleanSplit. This eases step 3.
    • You can tweak the new part in some directions with the gumball to make it fit as good as possible.
    • If needed, make a small negative ‘Offset’. This will reduce the quality of the result, but makes your life a lot easier.
    • Finally, make sure that as little as possible parts from the new part exceed the original hole.
  3. MeshBooleanDifferance
    • Firstly select the new part, secondly the original cup.
    • Now your result should be visible!
      Harry fixed
  4. Sometimes step 3 fails. A reason for this can be that the new part exceeded to much or that it was not a closed polysurface before step 3.
© 2011 TU Delft