Cleanpix Graphics

Creating VCAT Visual Evidence 3d Renders

Written on 22/07/2023 by Cleanpix Graphics

On some occasions, we receive client enquiries about supplying photomontage 3d renders of a proposed building design as part of their development application (DA) to the city council.

The purpose of these images is typically aimed at emphasising the design intent and compliance with planning regulations i.e. height restriction levels, overshadowing, neighbourhood character compatibility etc.

What is a Photomontage?

Creating a photomontage typically involves combining an ‘existing condition’ site photo of a specific property with a realistic 3d rendered representation of the proposed building design on top. The two layers are aligned to a matching view angle and tightly integrated to create a seamless image that shows off the new design in a set context.

This process is most commonly used to create exterior street view visuals or aerial views using drone photography for larger developments.

Office foyer interior 3d render
Office foyer interior 3d render

Above: A site photo of the existing condition and a photomontage of the photography and 3d render of the proposed building design.

Benefits of the Visual Evidence Method

While the traditional ‘marketing renders’ approach for preparing such images may be fine for a council submission, we always advise our clients to consider committing to a visual evidence solution for any ‘planning 3d renders’ in the event the application is escalated to a VCAT (Victorian Civil and Administrative Tribunal) hearing.

The visual evidence approach results in a far more accurate alignment of the photography and computer generated 3d graphics of the proposed design when creating the photomontage. This entails some additional steps in the overall process as well as detailed documentation of the methodology. Consequently there are some additional costs involved for this option but they are well worth considering.

In a VCAT hearing any supporting evidence that is submitted for consideration must meet a set of well defined criteria that is outlined in a set of guidelines (Practice Note PNVCAT2 Expert Evidence).

In short, for any computer generated visuals that may be presented, the parties must include a detailed report of the methodology used to create the images, experts involved, equipment and software used etc. All manual manipulation of the imagery and any embellishment must be avoided at all costs. Upon request, the studio or artist who created the imagery may need to be present at the hearing to respond to questions and supply testimony as an expert witness.

This is the main reason it is vital to submit photomontage visualisations that will be classed as ‘evidence’, rather than a set of 3d renders done in the marketing manner that any competent opposing party would denounce as ‘artist’s impressions’ and attempt to discredit and disregard.

Visual Evidence Process Outline

The steps listed below summarise the general process used to create visual evidence photomontage imagery:

  1. The initial step involves taking photography of the site in its existing condition. The view angles for the photos are typically advised by the client or their town planner. These photos will be used as the base layer of the final photomontage visuals.

  2. Once the photos are acquired and approved for use, a series of reference points are marked up and forwarded to a land surveyor with a request to collect AHD values (height levels) for these points.

    The survey data is essential for recreating the positions and angles of the virtual cameras in 3d space, relative to the 3d model of the proposed structure. This data is fed to the 3dsmax camera match tool which will solve the camera alignment without human interference.

  3. Office foyer interior 3d render

  4. Once the data collection is completed, the 3d modeling can proceed.

    A virtual 3-dimensional model of the proposed development is created in Autodesk 3dsmax by tracing CAD drawings (typically .dwg format) supplied by the architect. These drawings include floor plans, elevations, sections, site plan and landscaping schedules.

  5. Textures and colours are applied to the completed 3d model, corresponding to the proposed external finishes schedule provided by the architect or permit applicants.

  6. AutoCAD survey drawings are imported into the 3d model scene and the proposed building/subject model is positioned on top of the survey plan in the appropriate position in relation to the boundary (as drawn by the architects). The 3d model is raised along the Z-axis to the point where its floor and ceiling AHD values within the 3d space match the dimensions specified on the architect's elevation drawings.

  7. Special 3dsmax camera match point objects are created in 3d space and placed in positions indicated on the surveyor's drawing. They are then raised along the Z-axis to their surveyed AHD values.

    The point objects are virtual representations of the nominated reference points (see section 6.1) in 3d space. Their positions in relation to the virtual 3d model are identical to the same physical points in real life.

  8. A camera matching algorithm within Autodesk 3dsmax compares the placement of the nominated reference points on the photograph with the placement of the camera matching points in virtual 3d space.

    Based on this comparison the software uses a triangulation algorithm to create and position a virtual camera within the 3d space. The position and orientation of the virtual camera in relation to the reference points are identical to that of the real life DSLR camera used to create the photograph.

    Once the camera is created with the camera matching algorithm, it is set to the same lens size setting as was used on the DSLR camera lens when the site photographs were taken.

  9. Office foyer interior 3d render

    Above: After the 3dsmax camera matching tool creates the camera within the 3d model space, you can tell if the alignment is correct when the match points (white XYZ arrows) overlay the marked-up survey data points (yellow crosses).

  10. A sunlight system is created within the 3d space to mimic the position of the sun at the time of photo exposure. The 3dsmax sunlight system creates a light source at a specific azimuth, altitude and orientation dependant on user input data such as location (site latitude and longitude), date and time.

  11. Final rendered images of the 3d model are generated from the virtual camera's viewpoint and imported into Adobe Photoshop. The computer generated images are overlaid over the existing site photograph/s and areas of the proposed development that are obscured by objects in the foreground are masked out.

  12. An evidence statement document is prepared for submission alongside the visual evidence. This report addresses the VCAT expert evidence criteria including the methodology undertaken, data collected, parties involved, equipment/software used and various other statements.


Get in touch with us today to discuss how a set of visual evidence photomontage renders can benefit your town planning application. We have also prepared visual evidence images for objecting parties in the past as well. We are very happy to work with any party as long as there is no conflict of interest.