And the Environment seems to have adapted too
Saturday, July 7, 2012
Impressions
Cheap lens and bad lighting make it happen: Rainbow spotted!
And the Environment seems to have adapted too
And the Environment seems to have adapted too
Friday, July 6, 2012
3D Scan
Microsoft's Kinect Xbox camera is a pretty neat piece of technology. For little money you get a 3D scanner capable of a lot of things.
But as with most gadgets: Software's important. The internet is full of videos showing kinect-hacks, but working software in production quality is a little rare.
MeshLab to postprocess the scanned data, remove glitches and align multiple scans.
And finally Autodesk's 123D Make to transform the digital model to paper patterns to cut our model from.
The beauty of this approach is, that the ReconstructMe works with a metric space, allows us to measure distances and get the scale of the model right. 123D Catch, which extracts 3D data from videos or sequences of still images has no means of achieving that. You'd get a model, but no clue how big it is.
Second advantage is that ReconstructMe has access to the accelerometer inside the kinect, so the number of rotational degrees of freedom is reduced to one. (Actually they don't do that. From our own experiments with kinect raw data we assumed they would, because the software handles viewport direction changes that well.)
In principle ReconstructMe works in realtime, displaying the geometry it condensed from the kinect input, but you need at least graphics card power, as some OpenCL features are required.
But as with most gadgets: Software's important. The internet is full of videos showing kinect-hacks, but working software in production quality is a little rare.
Software
We used ReconstructMe, which is free for noncommercial use, to power the scanning process.MeshLab to postprocess the scanned data, remove glitches and align multiple scans.
And finally Autodesk's 123D Make to transform the digital model to paper patterns to cut our model from.
The beauty of this approach is, that the ReconstructMe works with a metric space, allows us to measure distances and get the scale of the model right. 123D Catch, which extracts 3D data from videos or sequences of still images has no means of achieving that. You'd get a model, but no clue how big it is.
In principle ReconstructMe works in realtime, displaying the geometry it condensed from the kinect input, but you need at least graphics card power, as some OpenCL features are required.
Realization
There were still some minor difficulties: First of all the the head is still up quite some distance from the ground. We had to build our own custom rig including aluminum tubes, a monopod and a mighty magic arm, mounting the kinect on top of it and climbe the pedestal beneath the horse to get a proper view.
Second, the kinect needs 12V power supply in addition to the USB. We had to wire some 1.5V batteries in series, tape cluster them up and hope that they'd last one mobile scanning session. Sadly there are no pictures of this operation.
As the laptop we had available didn't support all OpenCL features required, we didn't have realtime preview of the scan. We hat to scan blindly and hope that the data was good. Took us two sessions...
Here is a video of what the ReconstructMe processing looks like for a single take. Yes it's shaky, but remember, how high up the head is. You can see how the geometry is enlarged and refined as more of the head comes into view.
Next 4 individual scans (from the second session) covering different views of the head were combined and post-processed in MeshLab. This is the result:
Second, the kinect needs 12V power supply in addition to the USB. We had to wire some 1.5V batteries in series, tape cluster them up and hope that they'd last one mobile scanning session. Sadly there are no pictures of this operation.
As the laptop we had available didn't support all OpenCL features required, we didn't have realtime preview of the scan. We hat to scan blindly and hope that the data was good. Took us two sessions...
Here is a video of what the ReconstructMe processing looks like for a single take. Yes it's shaky, but remember, how high up the head is. You can see how the geometry is enlarged and refined as more of the head comes into view.
Next 4 individual scans (from the second session) covering different views of the head were combined and post-processed in MeshLab. This is the result:
Thursday, July 5, 2012
Time Lapse Day1
Day 1
First day at unicorniversity is over. Here are some impressions. Best part is that like 90% of the people passing by didn't notice anything.
Seems as if we made it look sufficiently natural. Problem is, this unicorn might starve to death. We guess, that at the apparent length and angle, eating grass might be impossible as the horn might touch the ground before the nose does...
Nice feature if you fall a lot. Might cause some severe headaches though.
Mounting detail
Nice feature if you fall a lot. Might cause some severe headaches though.
Mounting detail
We didn't match the exact color as the painted surface was rougher and thus reflected light more evenly (diffuse reflection) than the finished, weather proof epoxy based clear varnish, which reflects more mirror like (specular reflection).
Wednesday, July 4, 2012
Workflow
Steps necessary
The project splits up into supprojects: Building the actual horn and building a mounting platform.
Material of choice would be fiber reinforced plastics laminated to some kind of foam core. This way one get's a lightweight structure with controllable stability characteristics.
The first step, building the horn, is quite easy, as you've only have to get the scale right. As always size matters. Especially with part two, as the whole idea of the platform is to provide stability by closely matching the geometry of the head.
Material of choice would be fiber reinforced plastics laminated to some kind of foam core. This way one get's a lightweight structure with controllable stability characteristics.
The first step, building the horn, is quite easy, as you've only have to get the scale right. As always size matters. Especially with part two, as the whole idea of the platform is to provide stability by closely matching the geometry of the head.
As it's the 21 century and the head is too damn high above the ground to simply form a plaster mould, the way to go is making a 3D scan of the head. A Microsoft Kinect camera + the right software will do.
This way we'll have the geometry to construct the platform.
Ok, it's not as easy as it sounds, as we don't have a cnc-machine around, that could automatically get a real model from the digital data. We don't have a 3D printer either, but frankly the dimensions won't fit the regular ones those geeks out there are playing with.
This way we'll have the geometry to construct the platform.
Ok, it's not as easy as it sounds, as we don't have a cnc-machine around, that could automatically get a real model from the digital data. We don't have a 3D printer either, but frankly the dimensions won't fit the regular ones those geeks out there are playing with.
- 3D Scan the head to design the platform
- Software postprocessing
- Building a model of the important parts of the head from the digital geometry
- Use the model as a mold to create the platform
- Installing means for stripping down the platform, attaching some kind of string to it.
- Fitting the horn to the platform
Even though it won't be visible afterwards, the modeling part will be the most time consuming. But the investment into precision will definitely pay off.
A first glimpse at the topology of the head:
A first glimpse at the topology of the head:
The hole under the hair thingy would be ideal to route an attachment string through. And the plain head above the eyes should be wide enough to provide good transverse stability.
Planing Part 1
The question is how to build a unicorn.
Easiest way would be to stick something up there, that looks like a horn. A broomstick or something like that. In fact, what does that horn actually look like? Nature doesn't really dictate that. The last unicorns seem to have wandered this earth in medieval times. Albertus Magnus seems to have encountered one.
Common features are, that they are quite long and have a helical trench. Inspirational source might have been the narwhal. But their horn to overall length ratio looks impractical applied to a hose.
From a evolutionary perspective there must be some reasons for an equidae to carry one. We might get back to that discussion later...
Never the less, with narwhals in mind, most of the modern, pink-sparkling versions of unicorns hopping through the internet look awfully short horned. I leave it to the reader to fire up google and take a glimpse at that madness.
Requirements so far:
Easiest way would be to stick something up there, that looks like a horn. A broomstick or something like that. In fact, what does that horn actually look like? Nature doesn't really dictate that. The last unicorns seem to have wandered this earth in medieval times. Albertus Magnus seems to have encountered one.
Common features are, that they are quite long and have a helical trench. Inspirational source might have been the narwhal. But their horn to overall length ratio looks impractical applied to a hose.
From a evolutionary perspective there must be some reasons for an equidae to carry one. We might get back to that discussion later...
Never the less, with narwhals in mind, most of the modern, pink-sparkling versions of unicorns hopping through the internet look awfully short horned. I leave it to the reader to fire up google and take a glimpse at that madness.
Requirements so far:
- long (around the length of the head)
- helical carving(s)
- light, multiple reasons (safety,...)
- weather proof, should be up there at least 10% the time it took to build it before it disintegrates by itself
- inspiring, cause there are a lot more horses our there to enhance...
Most importantly we don't want to damage the original statue. So no hot glue, drilling holes or other unholy practices.
Strapping the horn to the head seems to be the best option. We ain't no engineers but it's pretty obvious that getting rid of the forces, both gravitation and occasional wind, can only be done with a big enough lever. In other words: the horn has to be attached to a platform, providing a sufficiently wide base, transferring the forces to the head.
Apparently the key difficulty is to make a platform closely matching the geometry of the head.
The Idea
Our university resides in a château. Nice to have. It even has a fancy statue in front of the main entrance. It's a horse. - But how if it would turn into a unicorn?
Just like that:
Pretty awesome, right? We know it isn't a white horse and of course doesn't shit rainbows, but the idea matters.
This blog will cover the whole process of planing, making and bringing the unicorn to our university.
Ok, not really concurrently. As we didn't want to put up information prematurely, not jeopardizing the operation. The horn is well in place when this site goes live.
So get out and watch for yourself.
Teaser:
Just like that:
Pretty awesome, right? We know it isn't a white horse and of course doesn't shit rainbows, but the idea matters.
This blog will cover the whole process of planing, making and bringing the unicorn to our university.
Ok, not really concurrently. As we didn't want to put up information prematurely, not jeopardizing the operation. The horn is well in place when this site goes live.
So get out and watch for yourself.
Teaser:
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