Hidden surface removal

[tom95521]

My knowledge of PTE is based upon a few hours each week during the evenings and weekends. It's just a hobby in my spare time.

Does PTE support hidden surface removal? If yes how is it enabled? I tried show front side and show back side options. I think it must already support this because there a so many slideshows that work properly. Examples are a cube and the very excellent first person perspective Christmas village (sorry I don't have the link).

http://en.wikipedia....e_determination

http://en.wikipedia....r%27s_algorithm

http://en.wikipedia....iki/Z-buffering

Microsoft API

http://msdn.microsof...6(v=vs.85).aspx

Sample slideshow. I think the red object would be hidden depending on location.

https://dl.dropboxus...bject_order.zip

Thanks,

Tom

[Lin Evans]

Hi Tom,

The answer is no. In order to make the red square disappear behind the blue one and apparently pass in front, etc., requires duplicating the red as a child of the blue, etc., and playing with opacity, position and size. It takes a bit of "trickery" to create the illusion.

Best regards,

Lin

[Lin Evans]

Hi Tom,

Here's a quickie for how I would proceed... I intentionally made it "not perfect" so you can see the "sandwich"

http://www.lin-evans...m/objectzip.zip

Lin

[PGA]

Tom/Lin,

Shortly after I produced my Rubik's Cube sequence, when version 6 had just given us 3D animation for the first time, I investigated doing a "Solar System" animation. My "proof of concept" used simple cubes to represent the Sun, Earth and Moon. I hit this same problem and raised the matter with Igor. He provided me with details of a "hidden switch" that was in the project file code and which they had experimented with during v6 development. They were not supporting that feature because it required the user to be on the then latest version of DirectX. At the time, the majority of users were still on Windows XP and the DirectX support had come in with Vista. I tried it out and it was the ideal solution to the problem of making an object disappear when it passed "behind" another.

Now that the world has moved on from Vista to Windows 7 and is moving steadily towards Windows 8, the overall level of DirectX in the user population must have risen significantly. Perhaps the time is now right for Igor and the team to activate that function. I wonder if we could persuade Igor to do it as part of the O&A rewrite promised for v8.5.

regards,

Peter

[Lin Evans]

Hi Tom,

Actually, although as Peter has discussed above, there may be a much better method in store for the future, it's actually not so difficult to do this for a complex animation as my little example might imply. I just used a very simple child example to demonstrate the "sandwich" idea, but in practice, were there to be several objects with complex motions and different circumstances, there is another very logical way to accomplish this as explained in my #33 tutorial here:

Link to relevant tutorial #33

Even though the tutorial linked above is titled: Move an Object in Elliptical Orbit and Make The Object Pass Both In Front Of And Behind Another Object the principles are very relevant. It might be worth the few minutes to download and watch.

Best regards,

Lin

[Lin Evans]

Hi Tom,

Hard to say - probably in the interest of compatibility like you surmise. Pay particular attention to the "copy/paste" of the frame and content which essentially duplicates the entire animation, but on the opposite layer which makes it exceedingly easy to simply opacity keyframe the object on the top layer out for passage behind another object, or leave it as is for passage in front. Essentially there are duplicate animations happening simultaneously but with no real overhead because of the way PTE works.

Yes, JPD was not only a great guy who unselfishly shared his ideas and amazing constructs, he also was one of the most innovative thinkers I've had the pleasure of knowing, even if it was only via the internet. He, like some others, were taken way too soon by a damned disease which should have had cures twenty years ago.

Best regards,

Lin