Perspective correction: Rectangle vs 8-Points

The perspective correction tool incorporates 3 separate tools: Force parallel, Rectangle & 8-Points (where I think the latter may be available only if one also has DxO Viewpoint - tho, I’m not absolutely sure about that).

Question: Is there any point in using the Rectangle tool, when the 8-Point tool is available ??

  • they both achieve the same end result (in so far as I can tell)
  • tho, I find the 8-Point tool easier/simpler to apply.
  • so, in which circumstances, if any, would I be better off using the Rectangle tool ??

Tip: When using any of the Perspective tools, it’s helpful to firstly apply it automatically, using the “magic wand” button (on far right) - as this usually does a pretty good job at setting the verticals & horizontals.

Regards, John M

Hmm Hmm John
@gerarto and me have written a tutorial expecially for ViewPoint and you have not read it :frowning:

Pascal

http://dxo.tuto.free.fr/ViewPoint/ViewPoint.html#8_correction_Perspective_Lignes_Points

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Hi Pascal,

I assure you - I have studied your tutorial on this topic (which I found especially helpful in understanding the Advanced Settings of the Perspective tool).

Your tutorial provides excellent examples of using both tools (Rectangle & 8-Point) - However, it doesn’t explain why one would necessarily use one of these tools in preference to the other (?)

I tend to always use the 8-Point tool - because, as far as I can see, it does everything the Rectangle tool can do - but is easier to work with (in my view).

John

The rectangle tool is faster to implement but more limited.
Nothing more :wink:

You will need VP3 for 8-Point tool.

Pascal

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And I may add that if you want a rectangle in your image, it should be easier with Rectangle to obtain exactly parallel sides.

Hmm Patrick
The result of these corrections is always parallel :slight_smile:
Pascal

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Yes Pascal,

I wanted to say that it may be easier with Rectangle to place the lines in the image where I think that it could be more difficult to ensure to place exactly the 4 independent lines in parallel of what we want.

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Yes. That’s why I prefer to use rectangular tool when I can.

Pascal

I’ve asked this question myself a few times and came to the following conclusion:

  1. force parallels has changed behavior: When I force verticals, the tool can also add some rotation. If I don’t want that, I use the 8 point tool (needs a VP license). Same thing for force horizontals too.
  2. Force rectangle: I use this if (and almost only if) I have a explicit rectangle like a window or picture frame etc. in the image. I only need to adjust four points with this tool and I can draw the initial rectangle targeting two corners on the go.
  3. 8 point tool: I use this in most cases, also for “creative corrections”.
  4. autocorrection: I find that it has improved but still does not work on all images. In these cases, I resort to the 8-point tool. Usually I try it only for either vertical or horizontal adjustments. BTW: Lightroom’s tool is similar (not perfect either)
  5. Sliders in the perspective tool: I use these when I want a physically correct correction (assuming that DPL works correctly) because some rectangles might look like rectangles but are not…
  6. finally, some things must be left uncorrected:

An excellent summary - Thanks.

John

I use “Auto mode” but with the restriction “Verticals only”
Pascal

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Same for me.

Thanks for this tip, Pascal - - I will try it out.

John

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