The correct way to do it
Although this may seem like “common sense” to most of you, from my experience I have discovered that there are actually very few clients that actually provide all the information needed to do a project, in a structured and complete manner.

Bellow I will try to lay out the guidelines of what would make an ideal info package (in my opinion, of course) in order to do an architectural visualization project from start to finish. Some of them

Camera view
This is probably one of the things that most clients skip when sending info to a freelancer. As I have mentioned in a previous article (How to ask for a quote), this part is most probably one of the most important. The reason for this is simple and obvious; in case of an exterior rendering for example, you don’t need to have the entire building modeled and mapped, but only the part that will be visible in the required view. Same thing goes for interior renderings.

I am not saying that the camera position should be pointed with 100% accuracy… I am saying that you should indicate it (on a cad file or a drawing, for example) to make sure that your partner will know what needs to be modeled. This way, the project will be finished sooner, and with a lower budget.

Basic modeling

a) For exteriors

-Exterior elevations, and floor plan(s).
If the building changes it’s shape a long it’s height (some floors have larger surfaces than others, or different perimeter shapes), than it is necessary to deliver all the floor plans. If not, just the ground plan should be enough.

-Sections
These are not always needed. However, if the building has some “special” elements, like an interior courtyard, and you need to show that in the rendering, than they are an absolute “must”.

b) For interiors
Usually, the basic modeling for interior renderings is easier to do, and require less information. A floor plan, and 1-2 elevations would do be enough in most cases. Sections are needed only if the space has some particularities (like extrusions, moldings, etc).

Materials

1) Photo reference
The first thing that I need to say here is that most of the time, only written indications regarding the materials is NOT enough. You need to provide as much photo reference as you can (remember that saying about a picture and 1000 words?). Why bother explaining textually all the properties of a material (shininess, color, transparency, reflectivity, etc.) when you can show a picture or two?
If you could provide correct and tileble textures it would be great for both you and for the one that’s doing the job than do so (this also depends on how you and your partner initially agreed upon, in the quoting phase)

2) Scale
Many seem not to take into consideration this step. Let’s assume that you have provided a texture of the brick, or a scan of a fabric material. It is very important that you indicate the REAL-life dimension of that sample, This way you won’t end up with 1m long bricks in the renderings. You might say that that could be corrected along the way, during the preliminary phases of the development of the project (which I will cover in a future article), but keep in mind that this won’ take you more than 10-20 minutes, while waiting for a revised rendering (for which you will still have to write comments) can take a lot more.

3) Which material goes where?
Obviously, for every material reference that you provide, you must be very specific regarding where it should be placed. This can be easily done, just by naming the file accordingly (ex. “Living-chair-no1-seating.jpg)

Furniture, lighting fixtures and entourage elements
This can be a little tricky also. Besides photo reference and indication regarding placement, you will also have to provide the dimensions for each object, no matter if it’s a piece of furniture, a lighting fixture or a vase.

Lighting
Last but not least, don’t forget to specify the time of the day that the final rendering will need to show. I know that this may seem like common sense, but I have met a guy that didn’t mention that he wanted a night rendering until he has seen what was supposed to be the last preview before hitting the high res rendering.

Final conclusion
This may seem like a lot of work to do, and most probably you don’t have to much time on your hands, but keep in mind that if you don’t do this at the beginning, you will eventually have make a lot of corrections during the preliminary deadlines, so not only you will have to write all of this at some point, but also, the it will take more time for the project to be completed.

If you are the one doing the work, make sure you ask for all the info that I have written above, before starting; it will make things more productive for both you and your client.

Good luck!