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Topic: largest synth + what computer for 1,100-photo synth?

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atrchi (Over 1 year ago)
So, attempting my first "serious" synth (a house, backyard, and surroundings)...

I took just over 1,100 photos.

Photosynth is giving me a warning that more than 300 photos "could take a long time".

What's the largest synth ever done? And what kind of computer would I need to buy/rent to do an 1,100-photo synth?

Thanks
Nathanael (Over 1 year ago)
Hi, ATR,

I wish that there was a simple formula to tell you exactly how much RAM you'll need for that many photos, but since each photo will have a different number of image features, I don't know how to estimate that very well. 

I can tell you that my biggest synths have been made on a computer with 4GB of RAM and my largest synth that I can think of at the moment had upwards of 1700 photos (each 10 megapixels) in it (although not all of them made it into the same point cloud and quite a few of them have miserable motion blur because I was rushing my shooting - both of these factors lessening the significance of the number of photos). 

I wrote a reply a couple of years ago on synth size limits which may answer some of your questions: 
http://photosynth.net/discussion.aspx?cat=ceca0f30-0f7c-4468-811a-32b623ea8563&dis=4e257d2c-bf39-44dc-8e81-4ec502ee1299
Nathanael (Over 1 year ago)
You should also know that the same computer that successfully completed several 1600+ photo synths for me was never able to synth a different set of around 1400 photos in a single synth, just based on how much the photos overlapped, so as I mentioned to Gavin earlier, no hard number of photos constitutes the maximum size of a synth.

I listed some of the largest synths I know of here: 
http://getsatisfaction.com/livelabs/topics/how_can_i_make_a_bigger_synth#reply_2876645

...

As far as the ideal synthing computer, free hard drive space is a necessity which almost everyone has but as far as the size of a synth you want to create, your only real limiting factor is RAM. 

A faster processor will speed things up, but RAM is the absolutely most important resource at your disposal.
Nathanael (Over 1 year ago)
A 32-bit version of Windows can utilize a maximum of 4 gigabytes of physical RAM. 
A 64-bit version of Windows can utilize a maximum of 8 terabytes of physical RAM. (No one has this much RAM yet.)

In 32-bit Windows, 32-bit applications (like Photosynth) by default can use up to 2 gigabytes of physical RAM while running in their own virtual 4 gigabyte virtual memory space. 

In 64-bit Windows, 32-bit applications (like Photosynth) by default can use up to 4 gigabytes of physical RAM while running in their own virtual 4 gigabyte virtual memory space. 
(This is contingent on you having enough physical RAM installed that after Windows and any other open programs use what they need, you still have 4GB of free RAM for Photosynth to use. In other words, if you have a 64-bit processor and 64-bit copy of Windows but your computer only has 4GB of total RAM, Photosynth will not be able to use all of it because Windows and any other open apps will be using part of your RAM.)
Nathanael (Over 1 year ago)
Ideal situation: You have a 64-bit processor, 64-bit copy of Windows, and more than 4GB of physical RAM installed so that after Windows + any other open software take their share, Photosynth always has 4GB of physical RAM to itself. This is the absolute best case scenario, given today's situation of being limited to a 32-bit Photosynth app.
Nathanael (Over 1 year ago)
Some tips for getting the most out of a computer, beyond installing as much RAM as possible: 

:: Windows itself will use some of that RAM and every open program on your computer will use some more of it, so when computing a large synth, it is helpful to close all unnecessary programs and background services and even features like Aero Glass in Windows Vista or Windows 7.

:: On a 32-bit copy of Windows, set Windows' virtual memory's paging file to its maximum of 4GB.
:: On a 64-bit copy of Windows, set Windows' virtual memory's paging file to 6GB or 8GB.

:: If you have multiple hard drives and the one that Windows is installed on is low on space, but another drive has lots of space, change Windows' 'TEMP' environment variable to point to a directory on the hard drive with lots of free space.

Those are the main things that I can think of at the moment. I'll post more if I think of it.
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