Positioning Background Images

[iggi]

Hi all,

I am very newbie and try to start creating a hull. I uploaded three images (same scale, I hope) but fail to position them correctly. The crosshairs in all three images seems to be in the correct position, but the overall perspective view doent look right.

 

I must be missing something very basic, I am sorry =)

 

[Maarten]

Hi Iggy,

 

Did you assign the right perspective? This determines where the image is placed (top, side, front/aft)

If you placed the cross hairs at the origin of your model (usually the aft perpendicular) the coordinates of the crosshairs should read 0,0 . Click the cross hairs symbol to open the coordinate window.

If this doesn’t work please upload a screen shot of your situation..?..

[Maarten]

I’ve made a very quick & dirty tutorial movie on placing and scaling background images (which will be called reference images in the next release:

Scale-background-images-1

• This reply was modified 2 years, 4 months ago by Maarten.
• This reply was modified 2 years, 4 months ago by Maarten.

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[iggi]

Dear Maarten,

Thanks a lot for the video.

Can you please advise me if there a rule how the DELFT interpret the size of the background images?
I mean, can I predict how large will appear an image say, 1200*600 pixels

The problem is that the method that you suggest of scaling is good if you already have the hull in the model, and then you can scale the image to fit it. However, it is not my case =(

Many thanks in advance,

• This reply was modified 2 years, 4 months ago by iggi.

[Maarten]

The size is ‘interpreted’ by scaling- I tend to use rather hight DPI for more accurate work as it gives nicer, smoother lines. It will slow down DELFTship somewhat though.

As for setting the scale, if you set a length for your model (you do this in the Project Settings, Main particulars window) the APP and FPP will be shown in the side (left/right) perspective. (as long as you actually have at least one surface modeled that starts aft of at the APP and ends at or forward of the FPP).

If you make sure all images have the same (relative) size, you will only need to scale the first image, the rest will be set at the same scale factor.

That said, we will aim to restore the function where you right-click on a part of the image so you can set the coordinates of the point.

[iggi]

Dear Maarten,

Thanks for the explanation, it worked nicely! =)

However, I am having another difficulty now. Sometimes (even in a completely new empty project) the Edit button for the background images is grey and I cannot add anything. Any idea why can it be happening please?

Thanks in advance!

 

• This reply was modified 2 years, 4 months ago by iggi.

[Maarten]

That can only happen if there are no main particulars – not a very commonb thing to happen.

Check the Project settinngs window, on the Main particulars tab, that all values, but at least the length, beam and draft are properly set

[IggNik]

Engineering programs have such a command – drawing calibration. Not just stretching or shrinking the picture, but calibration. This is when we have a known distance between the lines, we put two points on the line and indicate the distance between these points, and then the drawing changes proportionally to keep the distance between the specified points. This is what is missing in all programs in which reference drawings are inserted, especially for drawing bodies or hulls :))

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