Hi vramirez
Thank you for your enquiry on Lumion.
Will try to answer your questions without too much 'sales' type information

:
1. What is the resolution your are thinking of for 'large format'?
Here's a couple of samples, nothing special done to them, they do use some 'high quality' effects to enhance the look. So some
Global Illumination,
Reflections,
Speedray,
HyperLight 2. The subject matter may not be representative of what you are looking for, however it contains a building with full exterior modelling, some interior objects, exterior entourage, terrain, water for ocean and pool. It would be on the lightweight, simpler side of scenes that Lumion can do.
See pics attached, older slower GTX 980.
Email 1280x720: 6 seconds
Desktop 1920x1080: 12 seconds
Print 3840x2160: 44 seconds
Poster 7680x4320: 2 min 56 sec (too large to attach).
I recently read of a blog by a VRay user who talked in terms of 6 hours to render each single image (only 1080p), and it was still in draft, with final production quality being sent to a farm

.
Time to render of course can be adjusted for any softwares including Lumion, and will be affected by complexity of scene (buildings and entourage), effects used, high end effects used (for example
Hyperlight).
2. Most of the work is done on the GPU, not the CPU. Lumion currently uses only the one GPU. The performance of the rendering and working in Lumion depends on the capabilities of the GPU (cores, speed, amount of VRAM etC),
I'm not sure I understand your question about how often crashing occurs. Lumion is very stable, any 'crashes' of Lumion tend to be hardware related. That is, the user is trying to produce a scene with effects that exceeds to performance of the PC system, especially the graphics card. In 5 years I have personally experienced about 3 crashes, and each of those were from end-user files and could be put down to files corrupted on end user PC's (never experienced here) for example harddrive crash.
3. Some of our members may wish to comment on that.

It's done in-house, you have full control, the cost of expertise and time is far less than you would require if externally sourced.
We know that users (in some cases a single person) can create a scene, create animations and render them within 24 hours at 1080p.
4. Lumion requires the license to be validated only when Lumion is started, and again to close down Lumion and clear the license. In-between those points it does not matter about internet connectivity.
The examples from users in the Finished Projects and Featured Images and Movies Boards can also give you some indication of timeframes, output resolution etc. I would also suggest having a look through a few of the topics in the
Lumion Blog.
Should you require further discussions from a less technical support aspect, please feel free to contact your
local reseller and/or our Marketing staff: sales [at] act-3d.com.
You are also welcome to download the Demo version (see Try link top of forum) this is a no Save, not time limited version at v5.3 Or, request a 7 day Trial version from your local reseller which will be at version 6.0 (excluding some countries).