Parametric Arty Glass Model

lawrie

25 Jan, 2020 08:31 AM

A recent question asked on GrabCad is the inspiration for this quick tutorial. A Grabcad member. His task is tp produce a model of a existing glass tumbler. The basic model consists of two triangular profiles, the base profile separated from the top profile and rotated 180 deg. from the base profile. If you have the original in front of you it is possible to take a few measurements, but a big part of getting the final that you are happy with will probably involve a bit of tweaking to get something that looks right.

This concept can be expanded as by building a good robust model, by adjusting values in the function editor, one of the many useful tools available in Alibre Design software, many different versions can be produced with little effort.

Alibre Design is great product available for a price well bellow more fancied products like Solid Works and Inventor. For small time use Solid Works and Inventor are too expensive for the possibility of paying there way, which is why there are many pirated copies being used commercially. Alibre Design enables me to own an excellent tool that has paid its way.

1. Step 1:

   

   We start a new part model and save. Next make a new plane parallel to the base plane. We name this plane HEIGHT_1 and have given this a positive dimension of 70mm. As we have given this plane a name it can be easily located in the Alibre Design function editor. We can change our model by editing this and other values with the function editor.

   
   

2. Step 2:

   

   Now we start a sketch on the base plane as in the above image. This sketch needs to be fully constrained as we do not want it to come apart when we change driving dimensions. The sketch lines turn black when they are fully constrained. The driving dimensions have all been named so that they are easy to locate in the function editor. Dimensions that are the same as other dimensions are linked together so they update at the same time.

3. Step 3:

   

   Now we place a sketch on the HEIGHT_1 plane. Note that this top triangle is rotated 180 deg. from the bottom profile. In this case the sketch on the base plane and the HEIGHT_ plane sketch are fixed to the plane origin. It would be possible to dimension both these sketches offset from plane origin and to also dimension the angle of rotation between the sketches. This would give us two more adjustable parameters we can use to alter the look of our model.

   
   

4. Step 4:

   

   These sketches are now used to create a loft. The only check box I have selected is the "Minimize twist" box. You can play about with these options and see how they effect your loft. I have not drawn any 3D sketches to use as guide curves to control this loft as I feel I don't need them.

   

   Here is the lofted part.

5. Step 5:

   

   Now I create a sketch on vertical plane. Again this is fully constrained and I have given dimensions names so I can locate them easily. I will use this sketch to make a cut through the loft.

   

   
   

   
   

6. Step 6:

   

   Now we use the shell tool. The highlighted surface will be left open. I have given this shell a thickness of 3mm. I have named this variable for easy identification.

   

   
   

   Shell now complete.

7. Step 7:

   

   Radii can now be applied to parts of the model. I have made equations to set the size of these radii driven from the shell thickness value.

   
   

8. Step 8:

   

   I place a new sketch on the base of the part. I have constrained this to the edges of the bottom. This is extruded to form the bottom of the glass. We now have the finished part.

   
   

9. Step 9:

   

   The function editor can now be opened and by altering different dimensions we can completely change the shape of our part.

   
   

   
   

   I have, in this case used Alibre Design, but the same basic approach can be achieved with other software such as Solid Works and Inventor.