Thursday, November 11, 2010

Tgi3D SU PhotoScan Tips

Here are a few tips that may be helpful to make photoscanning complex amorph shapes easier. There is also a video showing surface fitting to photographs in action, if you haven't seen it already in Tgi3D's YouTube channel.

(1) Make sure the calibration is good. In Tgi3D Calibration Tool you can check the accuracy of the calibration by running calibration with “create calibration uncertainty (or accuracy) information” option. You can then increase the accuracy by going over the calibration points with the help of the "point errors" tab. You can add new points in different photographs to match existing calibration points or adjust the locations of existing points, and re-run the calibration process. In a human scale object the uncertainties of distances between calibration points should be at the order of millimeters for a good reconstruction.

(2) When applying surface fitting to photographs in SketchUP using Tgi3D SU PhotoScan plugin, the initial curves do not have to be exactly correct, they have to be close enough such that color based matching can arrive at the minimum from the given initial condition (a few pixels in the second picture). For that purpose actually, it is enough that one side of the surface is close to the real 3D, the rest of the surface will find its 3D location from that. The idea is to draw/match an easy (and possibly small) part of the object first, and then grow from there. You select the portion of the surface to be optimized, you do not want to spend optimization time on already optimized surface, but you want your surface to touch or include part of an already optimized surface.

(3) Also you can remove and put view locks and any part of the surface as needed. Do not hesitate to erase, repair, lock, unlock parts of surface as you see fit.

(4) If you have enough photographs, you can draw accurate curves using the silhouette of the object. This is sometimes useful. Imagine the silhouette of an arm from the side, you can draw the curve from front and if you have a side view you can position those curves from the side view. In fact if you have enough such silhouettes you can draw the object in 3D by using those silhouettes and simply creating and smoothing the corresponding surfaces without surface fitting to photographs, especially if you do not require a "numerically accurate" model.

(5) To draw curves on an object that does not have edges you may also make use of point-like features on the texture.

(6) One other thing that may be useful is to try to make the initial match with as few faces as possible. Do not increase resolution until you have a good match at lower resolution. Keep in mind though, if your resolution is too low you can never have a good match.

(7) Remember this is also a drawing tool, you can manually help the PhotoScan tool at any point, on any part of the surface with manual adjustments.

(8) For complex shapes some parts of the surface will remain hidden, or just have no texture on them, for those parts you can use smoothing operation. The smoothing operation guesstimates the surface shape from boundary conditions and softness/sharpness of the shapes.

(9) The photographs that you use should not have fake excess resolution. That is, do not increase resolution simply by changing image size in an editor. In fact, for most cameras you can decrease the resolution, decreasing the run time for PhotoScan.

(10) If you are making a really high detail model, you may want to create parts of the model in different SketchUp files, like head in one file, torso in another, legs in other etc, and then join them. SketchUp handles small polygon count files much better, try to remain under 5000-10000 faces per file, for example.

Wednesday, November 10, 2010

Launching Tgi3D Blog

We are launching this blog to provide 3D modelers with news about Tgi3D plugins for Google SketchUp. Visit often to find out what's cooking and to learn tips about using the plugins, to view models, how-to guides, and more...

Let me start with a quick introduction to Tgi3D and its products:

Tgi3D is a registered trademark of Ocali, Inc. With the launch of our website in mid-October, 2010 we have started marketing the two sets of plugins (Tgi3D SU Amorph and Tgi3D SU PhotoScan) for Google SketchUp under this trademark. We refer to our products as “sets” of plugins, beacuse each has a number of greate features that can be viewed as seperate plugins bundled in one.

Tgi3D SU Amorph allows you to create highly sophisticated 3D models by providing tools to create and edit free form curves and amorph surfaces. You can generate and manipulate curves and surfaces, increase resolution, edit extrusions, and do more with great ease. Tgi3D SU Amorph has a free Training version that has the same functionality as the commercial version except that it has a limit on the number of vertices two work with in some of its features related to surface meshes.

Tgi3D SU PhotoScan presents 3D scanning capability from photographs like never seen before in SketchUp. It is now possible to create highly accurate 3D models of complex real life objects in SketchUp. The Tgi3D SU PhotoScan package includes a seperate executable called the Tgi3D SU PhotoScan Calibration and Metrology Tool, which provides state-of-the-art camera calibration and metrology capabilities that can also report measurement uncertainties accurately. When the user is satisfied with measurement accuracy, the resulting calibration is exported to Google SketchUp, where the user then draws the approximate surface on photographs and Tgi3D SU Photoscan automatically corrects the selected portions of the surface by matching the textures in photographs corresponding to the selected surface. You can try the fully functional Tgi3D SU PhotoScan with the 30-Day Trial Edition.

To get more information about Tgi3D plugins for Google SketchUp
and of course