Each project is different, therefore, the time and effort needed for each one varies, so we need all the information about the project that can be provided to us to make a personalized offer*:
Number of images.
Plans (sections, facades, details).
References of materials.
3d model (some firms have their models, and that reduces production time and cost, although not required).
Once the budget is accepted, we start working on the 3d model (if it is not provided), we apply materials, cameras and lighting.
Later we send previous images in low resolution so that the client can see them, make corrections or change cameras. Once approved, corrections are made, postproduction and then sent finished to the client.
*It's not necessary that the project is finished to make an offer.