Typically, the client will spring for photo-realistic renderings when they want to go public with project for either planning or marketing purposes.

So, it's usually the client, not the architect who wants photorealistic 3D.

The architect doesn't need the photorealistic images to know what the building looks like. The client/public does. Besides, they're the ones paying for it.

But the architect needs phorealistic images to sell his ideas to the client, doesn't he?

By the terms of a standard AIA contract renderings aren't basic services. They're additional services, meaning the architect can't bill the client for them unless the client has specifically agreed to pay for renderings.

Some clients want renderings - for reasons discussed above - but many are not willing to add those services.

The architect may of course use renderings for his own marketing purposes, and there may also be situations in which he may choose to eat the cost of renderings on a particular project in order to provide that level of detail to a client.
But ordinarily if the architect is doing 3D models for his own use during the design of a project then he is often doing them for reasons that don't require photorealism (i.e. for massing studies, studies of intersections, basic lighting diagrams, progressions of spaces, views from and of building, etc.) and quicker in-house models may be perfect for his requirements, even if far inferior in terms of photorealism to what a rendering house might provide.

sometimes it can be required, such as in London, i think at times you need them..for large planning permissions...and then new approved view 3d has become a thing...where all dimensions are supposedly accurate in 3d...i do say supposedly...

Architects sometimes need/want flashy 3D renderings for competition entries or interviews for work. But I agree, typically it is a client driven request. In either case, they are generally for marketing purposes rather than design tools.

For most of the larger projects we have been involved with, our clients have needed photoreal renderings and animations. In my experience this helps them 'sell' these projects very efficiently.
It depends on the scale - for smaller projects, i think one can get away with no computer renders, but for the larger ones, they are a necessity these days.

Photorealistic 3D is comparably expensive, but if it was not, I think many of the designers and architects would use it during design process also.
Some projects still have a budget to afford showing many of design options to a client.

Indeed, is it often when you need to show a few options to the client so that he was able to choose?

Photoreal is mostly for the final marketing pieces, it is just too time consuming to use for the entire process. However, many clients need to see material samples to choose what brick color or accent color (and are shocked at how things really look!).

"photo-realistic renderings" - no such thing.

What's better then, if we talk about pre-construction marketing....???

Photoreal is what sells, the public does not want to see some architect's abstract interpretation of the building.


While artistic renderings look great for art's sake, they don't do much to help the client sell the building.

Have you ever faced the issue of lighting? Like... you may have a look at the lighting effect modeled by V-ray in photorealistic renderings...