3D Graphics poly render issue

swami_mathtraveler shared this problem 4 years ago
Answered

ISSUE:

- Poly rendering issue in 3D Graphics view. Sometimes, when adjusting a Duals 'Alt' slider (2a, or 2b), some polys stop rendering. This seems to happen when the object is expanded beyond the clipping box, then reduced back inside.


TO REPRODUCE:

- Open worksheet (https://www.geogebra.org/m/1374295).

- In 'Duals' panel, in 'Ray Method' dropdown, select '2a.'.

- Under 'Vertex-based', enable the 'All' checkbox.

- Adjust the 'Alt' slider.


SYSTEM CONFIGURATION DETAILS:

GGB VERSION:

- 5.0.134.0-3D

JAVA VERSION:

- 8 Update 51

BROWSER:

- Chrome, 43.0.2357.134 (64-bit)

COMPUTER:

- Mac PowerBook Pro

OS:

- OS X, Mavericks, 10.9.5

Comments (4)

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Notes:


- The polys are dynamically created (planes thru points in dynamic direction, then planes intersect at lines, these lines intersect at points, and finally, these points are connected as polys).


- Are polys one-sided. If so, perhaps some are getting flipped when they shouldn't.


- The render issue also occurs when adjusting the θ slider (in 'Basic Configuration').

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Clarification:


- The render issue also occurs when adjusting the θ slider (in 'Basic Configuration'), even when NOT is Ray Method 2a (or 2b), but also in 'Resultant'.

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More reproducing the error...


- Zoom way out, so object does not go outside the clipping box.

- Select Duals>Vertex-based>Ray Method>2b.

- Enable Duals>Vertex-based>All checkbox.

- Click label "Alt ratio" next to slider.

- Click repeatedly to cycle thru specific object configurations


Note:

- In this scenario, polys are well-behaved: the do not intersect of flip, yet the render issue still occurs.

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Still more...


- Click text label: Duals>"Vertex-based" to show poly values.

- pV1 => poly of vertex 1 (the top vertex of the Chestahedron).

- Note that pV1=0 for the special cases that can be cycled thru.

- For other configurations, some polys fail to be created. These have a value of "undefined".

- If a poly is undefined, the text label turns red to flag the situation.

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