Slideshow: The shadow diagrams were rendered at the stated times on the slides for select dates (Oct 21, June 21, March 21, Dec 21, Nov 26), renderings by Stephen Bohus, BLA. A photo of the rezoning information sign is also included in the slides (photo taken on October 25, 2021).
While there was supposed to be a rezoning ban on tower applications during the Broadway Plan public consultation process, developers are exploiting loopholes, and evidence shows that the City of Vancouver is actively encouraging and accepting applications. A number of blockbuster towers are already working their way through City Hall. One aspect of towers is their impacts on shadows, especially when towers are being proposed at a high point over a declining slope to the north, as we see in the case of the Fairview Slopes, which are home to thousands of residents and businesses. Is access to the sky important? Are shadow impacts important? Some may argue saying no, but we say yes. So the next step is to look at how the City actually deals with shadow analysis in preparing for public input and the final decision by our elected officials.
There’s a rezoning application in progress for a 24-storey office tower at 1395 West Broadway. The site is the current Toyota dealership site at the northeast corner of Hemlock and West Broadway. Despite the rezoning ban during the Broadway Plan, the City is advancing this application for Yuanheng BH Developments Limited (CEO Grant Lin). City staff are holding a Virtual Open House event that apparently began on October 18th and runs until November 7, 2021 (for more information shapeyourcity.ca/1395-w-broadway). Regarding the Virtual Open House rezoning at 1395 West Broadway, the City has not yet posted this information on the rezoning information signs (photos from October 25th).
In order to look at the cumulative shadow impacts in Fairview, we’ve included renderings that have three concurrent tower proposals. The renderings can be created interactively in real time at any time of the year, time of day and vantage point using the software package Unreal Engine (more on the model later).
Meanwhile, not far away, the rezoning application for a 39-storey tower at 1477 West Broadway will have a Virtual Open House run from November 15 to December 05, 2021 (details at https://shapeyourcity.ca/1477-w-broadway).
The 28-storey tower proposal at 2538 Birch Street is in the development permit stage and going to the Development Permit Board on November 15, 2021 (details at https://shapeyourcity.ca/2538-birch-st).
The shadow analysis by the applicant at 1395 West Broadway could be more nuanced, as our 3D model demonstrates. Included below is a snapshot of one of the shadow diagrams from the applicant’s submission (left), with the same time for a shadow rendering (our version on right).
The shadow diagrams in the application booklet (shadow diagram pages 34-37) used the following times: 10:30 am, 12:30 pm, 2:30 pm and 4:30 pm on June 21 (summer solstice) and March 21 (equinox). In our slideshow we’ve included the 2:30 pm times for comparison, and have also created a shadow rendering for December 21, as that wasn’t provided in the package (for December 21 the shadow at 2:30 pm stretches all the way to Granville Island). We have provided additional renderings in our slideshow with other dates and times.
The massing model of 1395 West Broadway was constructed based on the plans in the application booklet; the City does not have a model available. In the applicant’s booklet there are some minor inconsistencies between some of the drawings, renderings, and photos of the physical model (which most people won’t notice unless they try to build a model), but the information is sufficient in this case for a massing model. The measurements in the submission were in Imperial units, so a conversion to metric was done during the modelling stage.
It’s interesting to explore the shadow simulation at various times of the year and day. The City only looks at summer solstice and fall/spring equinox at a few select times (usually 10 am, noon, 2 pm and occasionally 4 pm as the standard, but some architects do more). There’s a really big difference going through October and to mid-November. In a situation where there’s a downward slope facing north, the shadow impacts are compounded. There’s a lot of discussion that could occur around the issue of solar access during the shoulder season. While it might be simple to dismiss the winter solstice as an extreme case (it’s commonly not included). Perhaps that’s true, but there’s a lot of time between the winter solstice and the spring/fall equinox, more precisely, half a year. Thus, the analysis and response could be far more nuanced. The City has specific guidelines set in place for the Fairview slopes because planning staff at one point looked in more detail at solar access. There’s also a difference in the impacts of tall buildings on the north side of West Broadway compared to ones on the south side, with the north side (which have greater impacts of the buildings are of the same height).
The 3D model we used for the shadow diagrams runs in real time. A user can navigate to any location, enter any date and time, and instantly see the shadows (or interactively scroll through times and see shadows update).
The software package used to create the renders was Unreal Engine 4.27 which can be downloaded for free here. The context data for the buildings and terrain was released by the City of Vancouver via FOI and used as a base. Additional modelling was done to create the proposed buildings and to supplement the City’s model (fill in missing buildings). Some other of the other datasets used in the 3D model came from the City’s Open Data portal (including aerial photography, property lines, LiDAR points).
References: Burrard Slopes C-3A Guidelines https://guidelines.vancouver.ca/guidelines-burrard-slopes-c-3a.pdf (last updated September 15, 2020)
shapeyourcity.ca/1395-w-broadway Virtual Open House October 18 → November 07, 2021