second 3d scan

To continue my efforts at scanning with the free DAVID 3d scanning software I decided to go for something a bit more interesting.
See the baby steps page for the very basics and a link to the DAVID software.

What I’m trying to achieve here

Ok on the First scan page you might have seen I scanned one side of a taped up coffee pot. For a start, it’s ok, but it’s not actually usefull in any way. Before I can do anything with a scan it has to be a scan of the entire surface of a model. This is not possible in one go, so once again I’ll have to improvise somewhat. So for now I’ll capture 5 scans, 4 quarters around my model and one from the top. Then I’ll stich them together and clean them up.


 

The clay model

I made a simple none too detailed clay model to start with. I figured I’d start with something round and cuteish. Later on I can always add detail. Maybe I should explain why… I am not interested in reverse-engineering. I am trained as an artist and to me, since I’m not a graphical artist, sketching in clay is nicer than doing so on paper.


 

A turntable setup

First of all, I needed something that would allow me to turn the model a certain ammount of degrees to scan each part. So I went out to buy a little turning platform from the local art supply store. I’m sure you can bodge something with a recordplayer, but it wasn’t too expensive. It’s not motorised so I marked out 15 degree increments around the outside of it. And yes, that is a cork with a nail in it! It is there so I can align my marks exactly with the tip of the nail. It actually really works well.


 

Better camera alignment

Ok so in my previous attempts I was just playing around. I think I have the camera alignment sorted now. You don’t actually have to see the entire big round circles at the top and bottom. Also it really helps if you have your camera at such an angle that you don’t see the “floor”. If you do see the floor, it will also be scanned. So try to set up your camera in such a way that it will only see the background and your model.


 

Scanning

So I did 4 scans of the model, turning the base 90 degrees after each scan. To get some better results I found that slowly moving the laser once from the top to the bottom and back worked fine. If I do a lot of moving back and forth I get nasty results. I also went for basic 320 x 240 resolution, I definitely don’t need more detail than that. It really does take a lot of experimentation to get your camera settings right, but it’s worth it to play around for a bit.


Importing the results in blender

So I have the scan data exported to obj format, now I import it into blender. Then rotate each object the correct ammount of degrees.


 

Aligning the results

Since I already rotated theobjects now I aligned them by eye so they match somewhat. I tried scanning with clues to alignment, but just doing it by hand seemed to give better results.


 

Cleaning the results

Now they’re aligned I went into top view and deleted the verts I didn’t need from each part. After doing this you can see not everything aligns perfectly but now it’s suddenly pretty clear what needs to be adjusted. Once that was done I simply filled in the gaps manually… not a fun job, but well… needed to be done. Oh and I’m not showing the scan of the top of the head here because I think this is clearer, so I did one more scan than you see.


 

Finishing up

Now I had a solid mesh I went into Blender’s lovely new scultpmode to smooth out some of the creases and horrid manual stitching.


 

A wireframe

Here is the wireframe of my final product. You can still clearly see where I manually stitched, but as a mesh it’s not that far from my clay model. 


 

A 3d render

I did a quick render in Yafray (installed that this week as well).


 

That’s it

I’ll leave it there for now. Next I’ll try something with a bit more detail though I’m afraid I may need a higher resolution camera.

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