AV Tutorial (SWF) on using JPD's Rectangles

[Lin Evans]

This little SWF file just shows how to manipulate an object as a "grandchild" of a rectangle. There are numerous cases when one might want to distort a shape such as JPD and Dom uses in their Photo Album templates (to get the effect of the perspective change as the page gets closer to and further from the viewer) or to simulate a rotor blade on a helicopter which is spinning while the helicopter is flying in a mostly horizontal fashion across the screen.

Many seem not to yet understand how this works so perhaps this little AV will help shed some light on JPD's discovery which he has put to amazing use in a number of demonstrations such as the six sided cube, the Photo Album, the modification of Tom's Helicopter, etc.

It's a zipped SWF file. If you don't already have a Flash 8 player, the free program IrfanView can easily display the Flash 8 SWF shows. Be sure to download both IrfanView and the latest Plugins.

http://www.lin-evans.net/p2e/rotorblade.zip

Best regards,

Lin

[Tomuk]

This little SWF file just shows how to manipulate an object as a "grandchild" of a rectangle. There are numerous cases when one might want to distort a shape such as JPD and Dom uses in their Photo Album templates (to get the effect of the perspective change as the page gets closer to and further from the viewer) or to simulate a rotor blade on a helicopter which is spinning while the helicopter is flying in a mostly horizontal fashion across the screen.

Many seem not to yet understand how this works so perhaps this little AV will help shed some light on JPD's discovery which he has put to amazing use in a number of demonstrations such as the six sided cube, the Photo Album, the modification of Tom's Helicopter, etc.

It's a zipped SWF file. If you don't already have a Flash 8 player, the free program IrfanView can easily display the Flash 8 SWF shows. Be sure to download both IrfanView and the latest Plugins.

http://www.lin-evans.net/p2e/rotorblade.zip

Best regards,

Lin

Lin,

Thats fantastic.

The button between the zoom controls was the bit I didn't find, your tutorial was just great,very easy for a "Dim Wit" like yours truly to understand.

Must go now as I am chaffing at the bit to have a go.

Thanks again for all your troubles,

To The DOM, JPD,AL, KEN,Peter and everybody else who took the time to help me , thank you very very much.

Tom.

[JPD]

and Dom uses in their Photo Album templates

Lin, I don't think that Dom use this function, his last album use curling effect of page and his Book Portrait use another method (black rectangle as mask which use rotate function).

[Lin Evans]

Hi JPD

Yes, I think you are absolutely correct. I just looked at Dom's latest demo of the book which uses the curling page effect and I do recall that he was earllier using the method I described originally with my very rough demo of how this effect might be created via masks. At one time I seem to recall that he had a flipping page effect which didn't seem to use the rectangle mask, but I didn't examine it very carefully so assumed probably incorrectly that he had adopted your parent/child rectangle as you described via the cube demo.

The nice thing that we all learn from the demonstrations is that there is more than one way to achieve an effect. When Tom first presented his demo of the helicopter I began to explore using PNG masks and such to simulate rotor flashing and constrain the rotor size but quickly realized that your solution was ever more elegant and straightforward.

Perhaps Dom can comment on how he was doing this with the earlier template.

Best regards,

Lin

Lin, I don't think that Dom use this function, his last album use curling effect of page and his Book Portrait use another method (black rectangle as mask which use rotate function).

[thedom]

Perhaps Dom can comment on how he was doing this with the earlier template.

Hi Lin,

My earlier template used your method. All explanations and history about this project are here : http://www.picturestoexe.com/forums/index.php?showtopic=4838

But the last one (see http://www.picturestoexe.com/forums/index....st&p=37265) doesn't use the curling effect of page.

The effect is done with multiple layers and dynamic shadows.

[Lin Evans]

Hi Dom,

Thanks for that explanation! I didn't remember all the details and hadn't been following the developments but I really like the latest version you are doing.

Both your and JPD's versions are great examples of what can be done with this great tool and some innovative thinking.

Best regards,

Lin

Hi Lin,

My earlier template used your method. All explanations and history about this project are here : http://www.picturestoexe.com/forums/index.php?showtopic=4838

But the last one (see http://www.picturestoexe.com/forums/index....st&p=37265) doesn't use the curling effect of page.

The effect is done with multiple layers and dynamic shadows.

[thedom]

Hi,

I started to work on a new project and I need to use JPD's method to simulate a 3D effect rotation (see images attached).

I would like to know how to calculate the deformation and the rotation to precisely adjust the objects.

I already did it visualy without any calculations and the result... needs to be improved!

Thanks for your help.

[Lin Evans]

Assume you begin at 180 degrees to the viewer and the diameter on screen of the tape reels equals 4 inches (you would need to actually measure the diameter) and further assume that the reel was a two dimensional disk (actually it's 3 dimentional). While rotating the projector through 90 degrees the appearance of the reels goes from 4 inches to zero so at 45 degrees the apparent diameter measured over the shortest distance would equal 2 inches and at 90 degrees it would be zero. So for each degree of rotation of the projector from 180 degrees relative to the observer you would loose .044 inches (90/4=.044). So if you determine how many degrees you want to rotate the projector and the initial diameter of the reel, you can determine the apparent diameter (distortion) at the shortest measurement by dividing 90 (degrees) by the diameter then multiply this by the number of degrees you rotate the projector relative to the observer.

The actual simulation you have looks fine to me. As far as the rotation, I think just confine the rectangle size and determine the RPM (revolution speed) you want via the rotation feature on the PNG and it should look perfectly natural.

Best regards,

Lin

Hi,

I started to work on a new project and I need to use JPD's method to simulate a 3D effect rotation (see images attached).

I would like to know how to calculate the deformation and the rotation to precisely adjust the objects.

I already did it visualy without any calculations and the result... needs to be improved!

Thanks for your help.

[JPD]

In order to do this effect you need 3 photos, the first one in front another from the top and the third one on the side, and I haven't think about the reels but you will probably obliged to do them with a cube with png files (one cube for each reels).

[Lin Evans]

Hi Dom,

I think I misinterpreted what you wanted to do. I was assuming you wanted to only rotate the reels with the projector at the approximate 45 degree angle as in the second image. I think JPD has correctly assumed that it's the projector you wish to rotate? Or perhaps have the reels turning while the projector is rotated?

In any event, as JPD says you will need three images to do this plus the separate PNG files for the reels. That's going to be a very tricky (difficult) animation but probably very nice once you accomplish it.

The calculations for the projector work very much as with the reels in that the appearance would begin with the "flat" 180 degree view then for each degree of rotation of the projector increase in apparent view by the percentage per degree until you reach the final rotated point. So you would want to measure the final width across the top and calculate it in the same manner in that when the projector is rotated 90 degrees (so you would be looking at the back) the "width" across the top would appear 100 percent. So at 45 degrees it would be half of it's full width in appearance.

You can probably best experiment first with a simple rectangle and rotate it over time to 90 degrees with the X axis and perhaps check the numbers at 45 degrees manually with the slider to get some idea of what to enter as values.

Best regards,

Lin

Hi,

I started to work on a new project and I need to use JPD's method to simulate a 3D effect rotation (see images attached).

I would like to know how to calculate the deformation and the rotation to precisely adjust the objects.

I already did it visualy without any calculations and the result... needs to be improved!

Thanks for your help.

[thedom]

Thank you guys for your answer.

I already had done something (see project attached, the images in my first post are screen captures of this project), but was not happy with the result. I made it intuitively and was wondering if there is a method to do calculations to make something "perfect". Hope I make myself clearer.

Do not pay attention to the files I used, it's only a quick and dirty version I did to know if it was feasible.

If I can make something I am happy with, I will make a fun and much more finalized template (will add a screen, spotlight, etc...) that can be used as an introduction to a slideshow by example.

Thank you for your help.

Project1_Mar6_2007_19_42_00.zip

[JPD]

if there is a method to do calculations to make something "perfect"

You must use trigonometry on the 3 axes X, Y and Z, and as it's enough long it's better to use a spreadshhet, without that, I wouldn't have a so good result for the cube. To find the good formulas in the spreadsheet, it take me about 2 days. For your work, I wouldn't make calculations, you just need to have about twice more keypoints and ajust at 500%.

Note : don't use frame so large, it's not usefull and need too much calculations.