Visual Programming of Canton Tower Model using Dynamo

INTRODUCTION

This project is an extension of the previously modeled Canton Tower using Revit. Dynamo is used to add certain features to the existing model. In the model, the top of the main body hosts a Ferris wheel which consists of 16 transparent pods circumnavigating in an elliptical track. Focus of this part of the project is mainly on these pods.

Firstly, dynamo is used to change the location of the pods on the uppermost elliptical track based on the sun settings, i.e. time. It is assumed that the pods will circumnavigate around the structure from 9 am to 9 pm and that the frequency is 1 revolution per hour for each pod. Consecutive pods are equally spaced between each other. Secondly, it is used to change the color of glass panels. The glass panels are meshed to form 6 bays separated by strips of metal sheets. 3 colors viz. blue, green and red are used to color the glass panels. Bays which are diametrically opposite to each other have similar colors. These glass panels will have light hues between 9 am to 1 pm; normal hues between 1 pm to 5 pm; dark hues between 5 pm to 9 pm; and regular transparent glass panels during the rest of the time.

POWERING WITH DYNAMO

Fig 1. The Dynamo program

This is the entire dynamo program which serves the objectives of the project. The 1^st part of the program dynamically changes the pod locations based on time and the 2^nd part of the program changes the color of the glass panels on the pods. The following screenshots will provide better description.

Fig 2. Time Retrieval from Revit program

This step retrieves the time from the Revit program. Since the raw time retrieved is according to UTC, it needs to be adjusted according to the local time in Guangzhou, China. This is further translated into total minutes which will be used in further calculations.

Fig 3. Determination of Location of 1^st Pod

The time range of operation of the pods are set between 540 and 1260 total minutes, i.e. 9 am to 9 pm. The normalized curve parameter of the 1^st pod are indexed from 0 to 61 (where 0 and 61 has same value). The corresponding values at each index will be assigned to the 1^st pod for each successive minutes.

Fig 4. Determine locations of other pods based on 1^st pod

The value of the 1^st pod location is equal to ‘a’ in this program. The other 15 pods will take the values based on this value. Since the value of the normalized curve parameter cannot be more than 1, all values greater than 1 are subtracted by 1 which is essential for proper operation of the program.

Fig 5. Assign calculated normalized curve parameter values for all the 16 pods

The 16 pod points are loaded on the program and listed. The controlling parameter is the Normalized Curve parameter which is defined by a string function. This meets the 1^st objective of the program.

Fig 6. Determination of current time on defined time ranges

The glass panel colors change at different time of operations. This part of the program identifies the current time and outputs the corresponding material index.

Fig 7. Material Database

The materials are assigned by index numbers. Based on the time range, a corresponding material list is invoked which will alter the glass panel colors in the subsequent step.

Fig 8. Assignment of glass panel color

All of the 16 pods are loaded into the program. The parameters needed for changing are identified by string functions and listed before it is fed to the glass panel color parameter changing function for the final step. This meets the 2^nd objective of the program.

THE GLASS PANELS

Fig 9. Glass panel definition based on curtain panel pattern based family

Fig 10. A transparent pod

This transparent pods is a hollow sphere extrusion. The glass panels are provided on the meshes created.

Fig 11. Transparent Pod defined on an adaptive point

This component is locked with the adaptive point which is hosted by the uppermost ellipse of the structure.

Fig 12. Example table of Glass Panel Color Parameter

VISUAL RESULTS

The following images describe the glass panel colors on different time ranges of the day.

Fig 13. Glass panel color during late morning

Fig 14. Glass panel color during afternoon

Fig 15. Glass panel color during evening

Fig 16. Glass panel color during the rest of the day

The following Graphics Interchange Formats highlight the essence of the 1st part of the program, i.e. circumnavigation of the pods around the structure.

GIF 1. Time range from 8:50 am to 9:20 am

GIF 2. Time range from 8:40 pm to 9:10 pm

This shows that the location of pods are programmed to change from 9 am to 9 pm with a frequency of 1 revolution per hour for each pod. 

Thanks & Gig'em.

Parametric Modeling of Canton Tower

Introduction

The Canton Tower is the 2^nd tallest observatory in the world standing at a height of 600 m. It is situated alongside the Yijuan Road in the Haizhu District of Guangzhou, China. Several famous landmarks surround the tower such as a few pagodas and a park, several high-rise apartments, buildings and skyscrapers. The tower appears as a luminous icon on Guangzhou’s skyline. An interesting feature about its lighting is that every node in the LED lighting design is individually controllable to allow for animations and color changes across the height of the tower.

Parametric Modeling

The main body of the tower is 460 m combined with another 140 m antenna. The tower’s twisted shape or hyperboloid structure is a state-of-the-art design. The form, volume and structure of the tower is generated primarily by two ellipses, one at ground level and the other at the top of the main body. Other series of ellipses are defined at various key elevations to place the mesh elements. The center and the orientation of these ellipses change with elevation which are defined parametrically with respect to elevation. Also, the major and minor radius of the ellipses change with elevation, the ratio of which is assumed to be a constant.

Fig 1: Ellipse at Ground level (+0.0 m) and at top of main body (+460.4 m)

Here, O_T is also the origin of the coordinate system. As we move up from the ground level, the ellipse shrinks to the minimum at the waist level (+280 m elevation) thereafter which it opens up at reduced rate as we go further upwards. Hence there are 2 rates of change of radius of major-axis and minor-axis – one from ground level to waist level, the other from waist level to top of the main body. Densification of materials causes limited transparency at the waist level. 

The center of the ellipses are determined by the following parameters with elevation (in mm) and angles (in degrees) as functions.

Table 1: Parametric equations for determining center and orientation of ellipse at different elevations

Here, ‘x-length’ is the horizontal component and ‘y-length’ is the vertical component of the parametric point with respect to the origin of the reference plane at ground level. ‘Ellipse Angle’ define the angle of major axis of the ellipse with respect to the vertical axis of the same reference plane. The following dimensions are used as a reference for the creation of ellipses.

Ground level	Major-axis length	=	78620	mm
	Minor-axis length	=	59180	mm
Waist level	Major-axis length	=	27500	mm
	Minor-axis length	=	20700	mm
Top level	Major-axis length	=	48310	mm
	Minor-axis length	=	36360	mm

Based on the above information, it was found that the parametric equations governing the center of the ellipses at key elevations are –

Length of major axis                       = 78620 – 182.571*y                    0<y<280 m

                                                       27500 + 115.355*(y-280)            280<y<460.4 m

where ‘y’ is elevation in meters.

Ratio of radius of major-axis to minor-axis                     = 1.328

Rate of change of angle with respect to elevation (m)     = 0.0847° per m

The key elevations are considered as follows.

Elevation	Level Name	Ellipse Angle (in degrees)
460.4 m	Open-air Top deck	0.0
424.0 m	Revolving Restaurant	3.1
408.4 m	VIP Restaurant	4.4
356.4 m	Future Development	8.8
174.4 m	Sky-garden refuge	24.2
169.2 m	Observation Deck	24.7
153.6 m	Snack-Bar	26.2
91.2 m	4D-Cinema	31.3
8.0 m	Entrance at Deck	38.2
0.0 m	Ground	39.0

Table 2: Key elevations and ellipse orientation angles 

Fig. 2: Top View of outer mesh of the structure model

OUTER MESH

24 cylindrical shafts run along the structural column core in a twisted manner. Braces and rings adorn the perimeter of the main body throughout its height.

Table 3: Parameters for defining radius of shaft, inclined braces and rings in outer mesh

The following images show the change in the size of the outer mesh elements.

Fig 3: Parametric outer mesh elements 1

Fig 4: Parametric outer mesh elements 2

CURTAIN PANEL

The curtain panel has a triangular form with rectangular and circular cross-section elements for which the dimensions are parametrically defined.

Table 4: Parametric equations for Curtain Panel elements

The following images show the change in the size of the outer mesh elements.

Fig 5: Parametric Curtain Panel 1

Fig 6: Parametric Curtain Panel 2

MASS MODELING

The mass of the central structure and the outer mesh is loaded into the project from 2 different files since Revit could not create floors when these were loaded from a single file due to the enormity of the structure. The central mass of structure has been divided into 37 floors throughout its height. The mass of outer mesh is placed in position such that it surrounds the central mass. The structure does not contain a roof since it has an open air deck. Curtain panels decorate the meshed curtain system created at the sides of the central mass.

Fig 7: Exterior rendering

Fig 8: Interior rendering

Thanks and Gig'em!