For a local history volunteering club I am looking to develop a walk-through version of the town in question through the ages. So I would like to offer the user a choice of centuries (1500, 1600, ..., 2000) and have him/her walk through the city, much like Google Street view, or even better, like Assassin's Creed in Florence and Paris. I am only looking at the part within the city walls. Maps are available going back till at least 1500. Switching between centuries means I would have to accommodate for changes in real estate, either in whole or in part, and perhaps even groups of houses. The street plan has not changed, apart from closing riverways.

As a start I would probably approach it as follows:

• obtain the x,y,z coordinates of all houses, as a rough guess 5000; complexity can be reduced in that houses are typically joined, so that a specific (x,y) of one house is the same as that of its neighbour.
• obtain photographs or drawings of each house as it would have looked like in each century and apply them as a skin to match the coordinates.
• find a viewer that will allow a user to perform a walk through, say HTML5.

Just to be clear, there is no AI, no story, no characters. Something like this might well be described as "skinning a static maze".
How is such a process normally done? What tools would be used? What type of relevant experience would we have to ask for in case we put this out in the market?

How much do you know about 3d modeling? The bulk of this work will be modeling each individual houses, and putting textures on them. 5000 is quite a lot. You could also go by creating a generic looking house that fits the architecture at that time, and apply that to all or majority of the houses, but it will not look very convincing.

Thank you for your response. Have never done 3D modeling. By the way, we would already be very happy where the result is a set of facades, ie without having to model the houses individually. It is just that these facades should line up fairly accurately with the street plan.

And then another multiple of that to cover the houses for every century.

It wouldn't be too hard to get someone to pull a couple hundred photos off the web, because about a third of the buildings are listed monuments and have a high-res version on the web.

The key however is to line them all up according to the city plan. What tools would be used for this?

A whole lot of the answer to this has to do with what "the town" means. Are you authoring an actual town, or rendering a hypothetical town that appears period correct?

It's a whole lot easier to describe to a program how to author a town than it is to author a town. Authoring a building by hand is easy, but the computer is better at doing things as stuff scales up. Render bits and pieces, like period correct doors and windows, and walls, and what a road looked like in different periods, and maybe even how roads are laid out in different periods. Describe to the machine how to snap all the little pieces together, and let it rip.

well, that sounds like a major project for a medium sized team to me (10+ people IMO)... how many guys will be working on it? Do you have any expierience with it, or is everyone a beginner?

What is your timeline?

Depending on your response, it might be quite difficult even with a limited scope (simplified buildings, simple walktrhough options) due to the historical correctness requirements and the multiple centuries you want covered, but fairly achievable...

Or it might be totally impossible due to too small team size, missing skillset or time restrictions.

The tools you need, given you do not want to start at zero (and write your own engine) would be: a 3D Package (Blender (free), Maya (lt version is not too expensive), 3DS MAx, others) to create the building meshes, a game engine (Unity Free version, Unreal Engine 4 (both free)) to create your scene and run the walktrough.

Preferrably you have some helper tools to extract the geo data and create the rough scene for you... this is not my area of expertise, but AFAIK some tools like that exist for the Unity engine, grabbing data from Google Earth and creating terrain, or even city geometry for you. No idea how far this will get you, and no idea if anything is free.

MAYBE there is a tool for Architectural pre-viz that can be used instead of the game engine. This tool will be much less flexible, and I don't know if there are free ones, but maybe worth a look.

The skillset you ned includes:

- 3D Modelling skills: Creating meshes, creating textures, UV Unwrapping, how to optimize meshes for realtime rendering.

- Game Engine Editor usage: you need to know your way around the editor of your chosen game engine... hardly rocket science, but will take you some time to get over the first bump of the learning curve

- Programming: Yes, you will need some programming skills. At least if you go with the game engine, not much, as your requirements are pretty basic. Just enough to let the user conduct his walktrough, and create the needed menus to select the era (Time of day, whatever you else add in options).

A whole lot of the answer to this has to do with what "the town" means. Are you authoring an actual town, or rendering a hypothetical town that appears period correct?

It is an actual town with maps, photos, paintings, drawings, digitised documentation etc going back to Roman Times. This is very much an actual town. This also means that we have multiple maps of the city plan through the ages, accurate to the cm.

The first step is to get the facades in and other street features are for later.