Observation point parameters

[JPD]

Jean-Cyprien and myself asked for the possibiliy to change observation point parameters. Today we are like a photographer who would have only one focal (41.6mm) and would always have the subject in the center.

I succeeded to simulate with actual V6 these parameters and can change the distance and the position of this point (that modify the perspective).

You will find an explanation and a demonstration here : Observation point parameters

[Lin Evans]

Hi Jean Pierre,

Excellent suggestion! Hopefully, Igor will be able to implement this in the very near future!

best regards,

Lin

[JPD]

Hi Jean Pierre,

Excellent suggestion! Hopefully, Igor will be able to implement this in the very near future!

best regards,

Lin

I hope so, Lin, I think it's easiest to do inside PTE than how I have been obliged to do, it's enough complex and too much difficult to do for users. It's necessary for instance for what try to do Umberto.

[thedom]

Very interesting idea because observation point in the middle of the screen can be a severe limitation right now.

If it can be implemented without beeing complex (and even hidden for users who do not need this parameter), I add my vote.

[xahu34]

Jean-Cyprien and myself asked for the possibiliy to change observation point parameters. Today we are like a photographer who would have only one focal (41.6mm) ....

This observation is closely related to the fact that the zoom function in the present version is a 3D-scaling, and not a zoom in the photographic sense (enlarged crop of the 2D view). It would be nice to have both kinds of zoom.

Regards,

Xaver

[JPD]

Thanks TheDom for your vote.

This observation is closely related to the fact that the zoom function in the present version is a 3D-scaling, and not a zoom in the photographic sense (enlarged crop of the 2D view). It would be nice to have both kinds of zoom.

Regards,

Xaver

I have well understand what you ask, but if we can change the distance of the point of observation, we can have the same result and do more things, no need to have two kinds of zooms which would be too complex for people. With a very long distance we can have a solid full screen without perpective and with a very short distance a very little solid with perspective.

Normally (but I am not a programmer), it's not very complex to do : only modify the calculation of the perspective, nothing else.

[xahu34]

... if we can change the distance of the point of observation, we can have the same result ...

Jean-Pierre,

Moving the scene forwards along the z-axis and make a photographic zoom obviously leads to a similar result as placing the observation point backwards. Moving the observation point off the center can be regarded as using a shift lens. As we know, the concepts are (more or less) identical. So, the questions is: How to explain it to the children, what is easier to understand?

It is needless to say that I support your proposal, regardless in which way this functionality will be called!

Best regards,

Xaver

[JPD]

Moving the observation point off the center can be regarded as using a shift lens

Yes or using a cropped photo

[CorVdK]

Hello, Bonjour Jean-Pierre,

Very clear explanation of the observation point parameters.

I have been reading also the mail of Jean-Cyprien on the Diapositif forum.

Count me in to support your proposal.

Thanks,

Cor

[JPD]

Hello, Bonjour Jean-Pierre,

Very clear explanation of the observation point parameters.

I have been reading also the mail of Jean-Cyprien on the Diapositif forum.

Count me in to support your proposal.

Thanks,

Cor

Thanks Cor, happy it's clear because it's not easy to explain such subject, many people had difficulties to understand this. A chance for us, Jean-Cyprien is very patient and give always good explanations

Here is the topic that Jean-Cyprien wrote on this subject last month (in french) on Diapositif

The problem is well explained and as usual a little humoristic. The english version of his file is there

Note When the topic was wrote, the two solutions I used in my file were not found

[thedom]

It is needless to say that I support your proposal, regardless in which way this functionality will be called!

Can we say that beeing able to modify the observation point is like having a camera object that you can put wherever you want ?

By example, you can put the camera on the grass to simulate what a bug can see ?

Or, on the opposite, put it at the top of a building to show what you can see from up there ?

[JPD]

Can we say that beeing able to modify the observation point is like having a camera object that you can put wherever you want ?

By example, you can put the camera on the grass to simulate what a bug can see ?

Or, on the opposite, put it at the top of a building to show what you can see from up there ?

Exactly. it's like you choice where you put your eyes or your camera (we need distance and position)

[xahu34]

Exactly. it's like you choice where you put your eyes or your camera (we need distance and position)

Just a remark: The 3D objects in the new version 5 of m-objects have parameters "camera position" and "distance"

Regards,

Xaver

[JPD]

Just a remark: The 3D objects in the new version 5 of m-objects have parameters "camera position" and "distance"

Regards,

Xaver

I didn't know, but it seems to me quite logical.

[xahu34]

A closer look shows that m.objects seems to have more sophisticated rotation parameters. So you can directly program a rotation of an object around a perpendicular axis, which can be done in PTE with the help of parent objects.

In m.objects, there is only one distance parameter in the Z-direction, but an additional field-of-view parameter. They seem to use the (slightly different, but equivalent) concept that I have proposed.

Regards,

Xaver

[JPD]

which can be done in PTE with the help of parent objects

It's why PTE is powerfull than others products. We often can do more things with Parents/children relationship.

concept that I have proposed.

Which concept ? Two kinds of zoom ?

[xahu34]

We should not dispute about nothing!

Important for the perspective representation of a scene is the distance between the observation point and the objects in the 3D space. So, here we need a distance parameter.

In order to specify what is to be seen on the screen we additionally have to fix a field of view. This can be done using angles, or using zoom parameters relative to a default view, or introducing a kind of focal length (something like the distance between the observation point and the screen), or ... (Many roads lead to Rome)

As said above: The existing zoom function in PTE is a 3D-scaling, and it does not provide the correct field of view.

Regards,

Xaver

[JPD]

Xaver, there is no dispute on a technical subjet, but I don't understand why you change a very simple problem in a complex one.

First the field of view is given by the screen itself and the distance (and also the position of the point), nothing else.

Second, it's easiest to have only one algorithm (or formulas) to calculate all the points of a 3D scene, with zoom as you describe their will be somewhere a "if" condition and at least two algorithms or formulas (that would means that objects with such zoom haven't the same observation point as others).

When my eyes look at a scene, it's the same, what I see depend only of the distance and the position where I am, and since I was born, it was enough for me. If the girl I look at is not enough tall, I haven't a vertical zoom to change her, neither an horizontal zoom if she is fat.

Simplest are the solutions, better they are, that's my opinion, but everybody have their owns.

PS I have think a lot as everybody on the problem of the zoom which give perspective. After several hours and many tests (screencopy and modification with Paintshop), I finally found Igor was right on this subject, same thing for rotations, a not very simple problem.

[JPD]

I think there is for some people a misunderstanding about the zooms and their normal influence on the perspective. So I created a small example (template + Exe) that attempts to explain.

I must add that changing the observation point doesn't change equivalent zoom of 100% for pan Z=0, if not it would be stupid.

[Etienne]

Congratulations to Jean-Pierre and Jean-Cyprien for their excellent work explaining the desire of moving the point of view.

It is a function of interest which will be an indispensable complement to the proper use of 3D features that allow the new version 6. 0.

I too hope that moving the point of view will be added in future versions.

[JPD]

Congratulations to Jean-Pierre and Jean-Cyprien for their excellent work explaining the desire of moving the point of view.

It is a function of interest which will be an indispensable complement to the proper use of 3D features that allow the new version 6. 0.

I too hope that moving the point of view will be added in future versions.

Thanks Etienne, as you, I hope.

[JPD]

Congratulations to Jean-Pierre and Jean-Cyprien for their excellent work explaining the desire of moving the point of view.

It is a function of interest which will be an indispensable complement to the proper use of 3D features that allow the new version 6. 0.

I too hope that moving the point of view will be added in future versions.

I hope i will have an answer before I am unabble to explain more if necessary