What are the Standard Perspective Views

[alanmac]

Whilst I don't have an answer to your question I'm intrigued by your comment regarding the credibility of the program. In what context. Are these people saying a camera gives a true perspective of a view and as such you should match to a given camera lens size ? Does any camera lens give the same true perspective view as seen by the human eye.

I'm no architect and my limited experience of local planning departments leaves me to believe, certainly in my area, it is all down to the whim of the planning officer either in charge or handling your application at that time.

From a position twelve years ago that an extension to the property must look as such, set back from the original building line etc. and not make the property appear larger or out of context to ones neighbours to a position now where more or less anything goes unless objected to by the neighbouring properties.

[canarch]

Alan,

what we are preparing is realistic views of our building within a city context. it becomes more of an Urban Design issue of illustrating the fit of our building into the surroundings.

we purchase a piece of the City's Model (toronto) and then import our own design. we then produce views from various vantage points and show the "true" impact our building will have on the city.

the vantage points obviously vary from project to project, i'm currently dealing with a 21 storey building where the city is less interested in height but rather wants to see the pedestrian impact at grade on the neighbouring streets, and buildings

previously this summer we had a project that was within a protected view Zone from a historic house. we had to ensure that we would not obstruct the view of the downtown core from a certain viewing balcony. thankfully we were simply the Architects and an urban Design Firm handled the Models for this court battle.

as for the Camera vs Eye issue. the majority of Urban design consultants that we deal with feel that when using this tool the use of a 50mm camera is close enough to the human eye that it gives legitamacy to the prepared image. it also allows us to import our buildings into an existing picture if we know the exact spot the photo was taken we can then set up a rendering of the building from the same point and merge the two.

in the past this work has been handled by other (some successfull some just not worth mentioning) we are constantly asked to prepare these types of images and i'd like to be able to within VW but obviously need the info as stated above.

hope this answers your question and intrigues others to answer mine.

Alistair Kirkwood, B.Arch.

Northgrave Architect Inc.

[canarch]

of the three standard perspective views that are offered in version 11 (Narrow, Normal, Wide) i assume that Normal is the closest to the human eye.

is it?

how can i find out the viewing angles or corresponding cameras that best match these settings. it is generally undersood that a50mm camera lens is closest to the human eye for perspective purposes.

the other question may be in the custom perspecive what numerical value can be added to achieve various camera angles or the human eye. is a chart of these values available anywhere.

this has become an issue for us as we present 3D views at Planning Hearings, the credibility of the program is now being questioned.

any help would be greatly appreciated.

thanks

Alistair Kirkwood, B.Arch.

Northgrave Architect Inc.

[Kaare Baekgaard]

With all respect, it seems to me, that what you need is to educate the persons at the planning hearings - and perhaps yourself - in the principles of perspective.

If you have not yet done them by hand, perhaps you should try that.. It is a surprisingly exact method.

If you go to a meeting filled with uncertainty, it is not surprising, that they will question the material, you present.

If you are confident and speak with authority, they will accept it.

[canarch]

quote:

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Originally posted by Kaare Baekgaard:

If you have not yet done them by hand, perhaps you should try that.. It is a surprisingly exact method.

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How very insightful. instead of actually using VW do a hand sketch. in the historical view mentioned above the view included an area of ?3km and about 2000 buildings, CN tower and the entire Toronto Financial District. if you can draw this perspective and ensure that all the buildings are set at their correct Geodetic heights within a week your hired.

quote:

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Originally posted by Kaare Baekgaard:

If you are confident and speak with authority, they will accept it.

---

i believe this is why i was asking for the information. other 3d modeling and Cadd software allow the user to chose camera lenses which then provide credibility to the evidence when submitted in court. simply calling the perspective NORMAL will probably be thrown out, much like your hand sketch would as you would not be allowed the time to demostrate your method.

perhaps the short answer is i should not be using VW which is not the answer i am looking for.

[CipesDesign]

Alistair, I do a lot of 3d modeling in VW's, however none at the scale (or scope?) that you require. I have used the program for a really long time and have always wanted better control (or even understanding) of the exact intent of the perspective settings. Here is what the manual says:

"The Perspective commands change the amount of distortion used to display the drawing, providing the impression of 3D perspective. Select from Normal, Narrow, or Wide perspectives, or create a custom perspective.

Narrow Perspective- Similar to a telephoto lens

Normal Perspective- Similar to a portrait lens

Wide Perspective- Similar to a wide angle or fisheye lens"

The choice of words are very clear: a pespective view in VW's is a "distortion" which gives an "impression". It would be very nice to be able to have a more precise method of matching a particular camera shot. Until then it's mainly a trial & error, do it til it feels right, kind of thing.:-)

Perhaps the programers can provide more specifics regarding the design intent of the various settings in order to utilize them more effectively???

[CipesDesign]

Sorry, one more thought: Boy are we spoiled! Up until a few years ago it would have been totally unrealistic to expect *any* of this from our computers/software. Look at how far we've come (and of course, the long road ahead...)!

[canarch]

Thanks Peter

i have already entered the manual's description into our evidence, but had hopped for a little more info.

your right lets hope someone from programming or tech support can help out.

does anyone know how the values work in the custom settings? other than what is stated in the manual

"Type the custom perspective value in the PERSPECTIVE field, and then click OK. the lower the value entered, the wider the angle of perspective."

does this relate to camera angles?

thanks

Alistair Kirkwood, B.Arch.

Northgrave Architect Inc.

[canarch]

quote:

---

Originally posted by CipesDesign:

Sorry, one more thought: Boy are we spoiled! Up until a few years ago it would have been totally unrealistic to expect *any* of this from our computers/software. Look at how far we've come (and of course, the long road ahead...)!

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again i agree, and for the most part what is offered with VW has been sufficient in the past. but once you add a few very highly paid planners, urban designers, and of course Lawyers you need to know exaclty what's happening.

telling a hearing that "my computer produced the image" is obviously not an option. same issue if you use VW to create actuall Shadow Diagrams we have to prove that the information inputed creates the correct shadows by referencing back to charts. something that I have done successfully in the past (thanks VW)

i guess with the increase in computer technolgy the expectation of accuracy has also increased (probably quicker than the technology) guess we'll wait for VW 20 which will include a Virtual Reality Plug in and only run on Mac G12's with a terrabite of Ram. ;-)

Alistair

[Jonathan Pickup]

there is a camera tool available for use with VW. It comes from :

http://www.ozcad.com.au

and it is part of the Architect Australia/NZ package.

if you need a 35mm camera lens equivalent then this will do it.

[Dave Donley]

Hello Alistair:

We do not currently have features in RW like perspective matching or standard camera formats for perspective setting. This is a wish that we would like to address in the future.

The camera used for rendering is a pinhole camera. It has a singular point as the location and it projects images onto a view plane that corresponds to your page held in front of the location by the Perspective distance.

If you use the Set 3D view menu command you can reliably place the camera's center of projection.

If you select a certain Perspective value (like Wide) then go to the Custom perspective dialog you will see the perspective distance used for each.

This value doesn't change depending on units; I believe the value shown is in inches.

To simulate a particular camera it would be necessary to use trigonometry to figure out the distances needed to match the format and angular field of view. You would also need to set the perspective crop rect to a correct size on the page for the format you wanted to simulate.

[Kaare Baekgaard]

Quote:

>If you can draw this perspective and ensure that all the buildings are set at their correct Geodetic heights within a week your hired.

Sorry if I upset you.

But am I wrong in assuming, that all these buildings are already there to be photographed - and that what you need to do is to document the impact of a new building in that context?

If that is the case, the angle of the camara lens can be read from the camera. The volume and borders of the new building can be established with great precision - by drawing extension lines from the corners of paralel, rectangular surfaces, establishing vanishing points and horizon. Using these with objects of known height and location to establish the excact borders of the new building mass, and fit the 3D model into these borders.

If these steps are followed, and the 3D model fits, it will be correctly represented. I can do this in less than a day, so can you. What am I not getting here?

[wv_vectorworker]

I have done this type of work successfully in West Vancouver. We had to prove that the view over a new building from a particular balcony would not be impaired. You need to experiment a bit to get it right. Model a known set of buildings and compare your "set 3D views" produced with photos of the same existing scene. You can show that the models are accurate with this kind of comparison.

As for hand drawn perspectival renderings, there is a young man in England who is able to do exactly that, he was shown on a BBC program taken on a helicopter ride over London, and then later making an accurate rendering of the city in a couple hours.

About two miles square and thousands of buildings!

[Delf]

To further complicate this discussion while I wander around trying to focus on the subject, a portrait lense is typically regarded to be about 80 mm when used on a 35 mm camera. Thus, the Vectorworks "Normal" setting would be too narrow (or slightly telephoto) to represent what people are generally credited with being able to see. As said by another, that's similar to a 50 mm lense. (When a photographer uses a standard 50 mm lense to take someone's portrait, the person's nose may be disproportionately enlarged ... and people don't like that since smaller noses are more popular.... so that's why they prefer the portrait lense.) Back to verifying if your image is 'normal.' A normal scene typically represents a 60 degree viewing angle. Of course people can see much wider (closer to 180 degrees, if their nose isn't too big and blocks some of the center of their view :-) )... so we use 'normal' to distinguish our more detailed field of view instead of the broader view with peripheral vision. It isn't too hard to display a 60 degree angle on your site plan for the planning commission, and to correlate that with your illustration. But I suspect any planning commissioner raising this issue will never be really satisfied by an answer, since the entire concept is hard to pin down. Just smile and point to your work as being accurate.

[ErichR]

Delf's excellent take notwithstanding, my experience is that the 'Normal' perspective setting would correspond to about 80-90mm. I think if you experiment, you will find that VW's perspective marquee width will adjust when changing the\ setting to Wide, or otherwise (the underlying perspective being the same). This being so, and analogous to manually constructing the perspective, the wider the viewing angle the more distorted will be the result. "Normal" is relative, as others have pointed out. I'm very myopic and my specs make things a bit rounded on the periphery. Is this normal? It is for me.

[Brian R]

One can set views from specific viewer locations/eye-heights to specific objects with accuracy in Design Layers; we use it to quickly illustrate sightlines to theater stage from specific seats, and it is very effective.[This was why we bought the Vectorworks to begin with!]. I wish the Viewports views had specified viewer heights, but they don't and are not as accurate as I need, so I still have to go back to the Design Layer and set up a layer link to get the whole picture. As for "normal" etc., I crop out the distorted picture on the periphery (stretched people etc.). I guess it is a subjective call to say what looks "distorted".

[mike m oz]

Julian Carr at OzCAD has developed a camera tool which comes with the Australian version of Architect. It will do exactly what you want. You can have multiple cameras in your model and even give them names.

You initially set up the camera in the Top Plan View. Controls to then refine the view include:

- Camera Height (z)

- Look to Height

- View Angle

- Aspect Ratio

There are 3 view option buttons on the OIP:

- Perspective Camera View

- Orthoganal Camera View

- Top/Plan View

Clicking on the appropriate button takes you to that view.

Very simple and very effective.

Contact julian and ask if he will sell it to you. www.ozcad.com.au