Forum : Advice & Critiques

Can’t seem to get something to synth right? Curious about what lens is best? Ask your fellow Photosynthers here.


Topic: Photosynth questions

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efbld2f (Over 1 year ago)
I did my best to take dozens of pictures covering every part of my balsa wood airplane, my dogs, and a detailed panorama of my living room, but it just isn't working.  I only got a 41% synth and I can't seem to pan 360*.  It just doesn't let me go more than about 270*.

Further, I have looked everywhere and I can't find a way to create a 3d view of something.  That is to say I want to take several pictures from all angles of something (my airplane) and be able to circle around it.

Any help is greatly appreciated.  Let me know if you need more information.  Below is a link to the synth that I just failed at.

http://photosynth.net/view.aspx?cid=a93c8771-6bec-4db3-9caa-68b99e9294fe
Nathanael (Over 1 year ago)
Welcome to the Photosynth community, efbld2f!

First and foremost, if you haven't already downloaded the Photosynth Photography Guide, you can get it here: http://photosynth.net/help.aspx#photosynthhelp

There are a lot of important tips in there like not moving more than 25 degrees around something between two individual shots of it and getting three shots from three different positions of any part of the object or scene that you want to see in the point cloud. 

I know you may be thinking, "I took more than three photos of the plane!", but try to think of individual parts of the plane. Take the rear wings, for example. How many photos can you see them in and did you move more than 25 degrees between those views? Where you did, the matching will likely fail.
Nathanael (Over 1 year ago)
You may also remember Laura saying in the 'How to Synth' video (viewable at http://photosynth.net/create.aspx ) that Photosynth doesn't look at shape, but at texture. You'll find that the Photosynth Photography Guide also says this.

In many of your photos of the plane the wood is overexposed by the light in the room, meaning that the pixels that represent the balsa are almost pure white. That means that there isn't any wood grain for Photosynth to memorize. 

Another thing that makes these photos of your plane a challenging subject is that it is constructed of very thin pieces of wood. At the distance you shot them, the wood strips are very small portions of the photos. 

If I were trying to synth your plane, I would choose several important parts of the plane to completely circle with photos. 

Examples: 
each of the front wings 
the tail and rear wings 
one of the whole body 
etc.
Nathanael (Over 1 year ago)
Here are a couple of examples of the sort of point clouds you can build by just circling a few important parts of the scene: 
(Use the [P] key to toggle the photos and point clouds or use [T] for Overhead View.)

http://bit.ly/orbitalsynth 
http://bit.ly/woodensynth 
http://bit.ly/tablesynth 

Don't be put off by the large number of photos that I used. I tend to shoot more than is strictly necessary, just to see how thick I can get some parts of the point cloud, but you can still have success with far fewer.

There's nothing in Photosynth that needs you to take photos in inward looking circles, but taking photos that way is a helpful way to help you mentally organize what you've already shot and what you still need to shoot.

If you have any questions, by all means, ask away. Remember, you have the same exact program that I used to put those together. The only difference is how we took the photos.

All the best!
Your fellow photosynther, N.
efbld2f (Over 1 year ago)
Hmm ok great.  Thank you both.

Nate, are you saying that if I get a bunch of usable pictures of an object, I can make a 3d, 'spinnable' model that I can look around all sides of?
Nathanael (Over 1 year ago)
It really depends on what you mean by 'spinnable', I suppose. 

You can certainly rotate all the way around the table or the wooden sign by clicking on the circular arrows and dragging them side to side. The flowers example is a bit more complex, though you should be able to rotate around most of the blooms that I shot that day.

What is more, if you're viewing the point cloud with the photos turned off, you'll see that you can rotate it to angles that I never took photos from.

Here are some links for the same synths in the older faster Photosynth viewer (requires Internet Explorer or Firefox 3 for Windows - not Firefox 4): 
(Here, instead of the circular arrows seen in the Silverlight Photosynth viewer, you'll see a halo that you can grab and spin.)

http://bit.ly/orbitalsynthd3d
http://bit.ly/woodensynthd3d
http://bit.ly/tablesynthd3d
http://bit.ly/hydrantsynthd3d
http://bit.ly/dougsynthd3d
efbld2f (Over 1 year ago)
I understand.  Taking your advice, I did a simple synth of my room (I'm moving and it's kinda a mess) and nailed a 100%.

Thanks for the help.  Now I understand what I need to do and I'll do something better tomorrow.

http://photosynth.net/view.aspx?cid=e94a6735-9a9e-4c3e-b149-152f69ae777c
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