In the big cities, there are many architectural designs around. Look at the skyscrapers. Ignoring the pros and cons of the eternal discussion form versus function, we sometimes find very creative projects lost in a sea of straight lines. Such creativity is expressed, for example, by the twisted forms found in projects like the Cayan Tower, in Dubai, or the Twisted Torso, in Sweden, or Al Hamra Tower , in Kuwait. That said, the goal of this post is present you a procedure to create twisted forms in ANSYS Design Modeler and ANSYS SpaceClaim.
Cayan Tower (Infinity Tower) – Dubai Marina
Cayan Tower, the 75-storey residential tower that spirals in a smooth curve by an astonishing 90 degrees to give every apartment a stunning view of the sea or marina. Cayan Tower´s dynamic twisting shape challenges conventional architecture and redefines standards of luxury. (reference)
Let’s do the twist
Different CAD tools have different approaches to handle twisted forms. Some are pretty straightforward, some require some effort to proceed. Let’s start by modeling a twisted tower using ANSYS Design Modeler
With ANSYS Design Modeler openned, click the item Geometry > ZXPlane
Click Sketching tab, and then on the Rectangle tool in the group Draw.
Click on Dimensions group and then on the General tool
Click on the vertical line to add a dimension. Repeat for the horizontal line
Change the dimensions at the property view. Both vertical and horizontal line must be 30m
Center the rectangle with respect the origin. Click on Horizontal tool and add a dimension between the vertical line and the vertical center axis.
Repeat the procedure for the other side of rectangle, this time using the Vertical tool.
Change the value for these new dimensions to 15m.
ANSYS Design Modeler – Base Rectangle – Center
Create a new plane, by clicking on the New Plane tool, using as a Base Plane ZX Plane.
Change the Transform 1 (RMB) property to Offset Z.
Change the FD1, Value property to be equal to 60m.
Click on Generate to apply the changes.
ANSYS Design Modeler – Create Plane
Create a new Sketch ih the Plane4, repeating the procedure described in the steps I, II and III.
RMB click on the Sketch2, select Always show sketch. Do the same with Sketch1.
Click on the blue ball in the triad and then hit F7 to zoom to fit (to see the sketches in perspective)
ANSYS Design Modeler – Top Square
Select both scketches in the treeview, by clicking on them while holding the Ctrl key
Click on the Skin/Loft tool. In the Profiles property, click on Apply to confirm the selection
Click on Generate to apply the changes and create the solid.
ANSYS Design Modeler – Solid
Finally, let’s twist! RMB click on Plane4 and select Edit Selections.
Edit the property Transform 2 (RMB) and chose the value Rotate about Z.
For the property FD2, Value, define the value 90º. Click on Generate to appli the changes.
Done! We have the Twisted solid!
ANSYS Design Modeler – Solid Twisted
You may have noticed, the twist process also generated a “waist” in the half of the tower. This could be intentional, as we can see in the Canton Tower, in China:
The original shape of Canton Tower is a beautiful and elegant lady with a slim figure, and such a unique shape was inspired by the bones of human hip joint. In order to create slenderness and softness of a female, the designer Mark Hemel tied the two oval wooden trays up by elastic rubber ropes to form a three-dimensional sculpt. When he rotated the ellipse at the top by 45 degree, a marvelous shape which resembles a fried dough twist appeared. And that’s the inspiration of Canton Tower – a fair lady twists her waist while looking behind.(reference)
Open ANSYS SPDM (SpaceClaim Direct Modeler). Verify if the lenght unit in use is meter. Click File->SpaceClaim Options to see the SpaceClaim Options dialog box. Click on Units and select Meters in the drop-down list Length.
Scrow down and define 1m in the Minor grip spacing and 10 to Number of grid lines per major. Close the dialog box.
Ensure that the option Snap to grid is checked.
ANSYS SpaceClaim Direct Modeler – Snap to grid
Use the hotkey R to select the Rectangle tool. Click on the origin point to define the first rectangle corner.
Type 30 to define the side lenght of the rectangle. Then, hit Tab key and type 30 again to define the other lenght.
Hit the hotkey D to change the view to the 3D mode and create the surface
ANSYS SpaceClaim Direct Modeler – Base Rect
Hit the hot key M and then click on the Move grid tool in the panel at the left hand side
Click & Drag the blue axis upwards, and hit the space bar to open the inline editor. Type 60 and Enter.
Hit the hot keys V and Z to see the Plan View and to zoom to fit, respectively.
ANSYS SpaceClaim Direct Modeler – Move plane
Repeat the steps II-1 and II-2 to draw the upper rectangle.
Hit the hot keys D and H to create the surface and to see the perspective view, respectively.
Select the upper rectangle and then hit the hotkey M.
Click & Drag on the blue arc. While dragging, hit the space bar and type 45 and then Enter to rotate the rectangle.
ANSYS SpaceClaim Direct Modeler – Upper Rect
Hit the hotkey B to activate the Blend tool. Select the two surfaces in the tree (Ctrl + Click).
A preview of the solid is shown. Click on the gren check mark to create the solid.
Done! We have the Twisted solid!
ANSYS SpaceClaim Direct Modeler – Solid Twisted
You may have noticed, for the ANSYS SpaceClaim, the rotation angle was defined as 45 deg. If defined 90 deg, the solid would not twist as expected.This is due the fact that ANSYS SpaceClaim doesn’t keep the coordinate reference position. Do you have any suggestion to overcome this limitation, or maybe an alternative (better) procedure to create twisted forms in ANSYS SpaceClaim? Please comment!!