Little background. I am currently developing First person game like project. For that I am making 3d Architecture on the software 3ds max. The project has over 25 rooms which will be present on one scene. Currently I have developed 5 rooms which are over 700000 polygons.The issue which I am facing that the 3ds Max is keep crashing due to huge number of polygon. Now how can make all the rooms on one scene in 3ds max. Any suggestions?

I like to draw engines. So let's say I have valve stem. To make it look round I use 32 polys all around. Then along the shaft some 15 polys. Then I need 4 valves per cylinder. I may have 12 cylinders per engine. So MULTIPLICATION everywhere. Still: 7 Millions? For Architecture? The kind of poly model that the original Doom uses because it is so easy on the computer?

A little background which I should have added earlier. I am making a first person tour on which you can interact with the environment. The game engine will be used to for the development of this project is unity game engine. The problem is I am working as a modeller in my group. My job is to model the complete rooms in 3ds Max then have to export to Fbx format from there my team members will carry out the others areas of the project such as working in Unity programming, audio , menus etc. In this case what can be done by me as 3d modeller using 3ds max?
More info: Each room which I have created has minimum 25000 polygons.

Basically your options are:

• Try a different software package to see if it can handle bigger files.
• Upgrade your computer. You will want a ton of main memory and a ton of video memory.
• Don't. Create your individual pieces as separate files. If you need to see where different pieces are in relationship to each other, use lower-resolution models for that.

700,000 doesn't actually sound like all that much to me. As an experiment, I started Blender on my computer and started subdividing a cube to see what my computer could handle. I got all the way to ~25,000,000 without crashing, although performance was pretty bad at that level. That's about the limit on my computer - Blender says that it's using ~28GB of memory, and I only have 64GB of physical memory, so I'm not going to attempt another level of subdivision.

This is usually a bad approach! The “normal” workflow is to model anything in separated files. I don't believe that a room with nothing in it will need 7.000.000 polys for just walls and a door so remove anything that isn't part of the room architecture to separate files. Those are then assembled to rooms in Unity because Unity can handle those Assets better than Max, Max is not a game engine. Also you don't have to model the same table over and over again, it is instantiated and saves A LOT of memory in the game