Components improve with multiple runs of Align?

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    Götz Echtenacher

    Hi Tom,

    this is an interesting observation.

    In general, you are right, RC does use previous alignments for subsequent ones. But I am pretty certain that they have to be present in the form of a component in the same project. So in theory you only need to delete all components to start from scratch. As far as I understand only features are stored in the cache (which you did not empty, right?).

    It could be coinsidence, since there seems to be a randomness in the alignment process, which gets more apparent with difficult image sets (which yours seems to be).

    Could you try a couple more times and see if it produces a worse result at some point? That would help to verify my theory...

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    Tom Foster

    Trying many combinations - Align Normal and Align Draft, with/without deletng previous components, with/without deleting cache temp, not ar any point saving as a project, the Components produced are pretty consistent - no further improvement. If anything, Draft gets mostly 40 in the main Component, Normal gets 39. Why today it suddenly came up from 25 to 35 to 40 is unexplained - previous days' similar tries it stayed consistent around 25.

    I noticed that the no of files added to cache temp equals the no of photos in the project - 55, not increased by subsequent Aligns. Except that switching from e.g. Align Normal to Draft adds another 55 files - 110. Back to Normal does not add more files - remains 110.

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    Götz Echtenacher

    Ah, very nice observation - so it really only is the features in the cache. That means that the rest must be stored in the component. By that logic my theory was correct and deleting all components should be the same as starting from scratch. I guess it was coinsidence that your alignment slowly improved - I had some of those too which lead me to wrong conclusions at the beginning...  :-)

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    Tom Foster

    Remember I've only got as far a Align - no Reconstruction yet in this experiment - which might add additional temp files.

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    Johnathon

    I often start with reprojection error adjustments by .5 at a time to improve my component(s) i.e. align; then R.E. 1.5; align; R.E. 1; align; R.E. 0.5; Align

    Hope that helps

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    Götz Echtenacher

    Hey Tom,

    it's all good since the alignment step is the important one in this case - bad alignment, bad mseh, bad texture...

    Hey Johnathon,

    that's good advice to improve a well aligned model in the details, but since Tom seems to be having difficulties getting any kind of features on his surfaces, reducing the repro error might be counterproductive. But I guess it might be worth a try.

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    Tom Foster

    I have moved on to other experiments, but here's another curious result in yesterday's:

    Yesterday, repeateble stable result for fresh projects (everything incl cache deleted and photos re-added) varied slightly around:

    Normal align: 3 components of 39, 4, 3.

    Draft align: 3 components of 40, 5, 3.

    After a day away, Normal align degrades to 3 components of 35, 4, 3. Re-run with Draft align improves it to 3 components of 40, 5, 3.

    Draft align: 3 components of 40, 5, 3.

    Draft align again: 2 components of 42, 5!

    So with Draft it continues to creep up, with Normal liable to drop back!

    Now playing with Draft's 3 setting options - the default works best.

    Next - to play with Normal's (or rather, the Alignment>Align button) 5 setting options.

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