Line rendering glitch

hi all,
i have trouble understanding a problem i’m facing when rendering a set of lines (based on Delaunay triangulation).
hopefully the images help illustrate the issue: in the first one, the rendering is correct. the second one is the same image, but with a little different camera orientation & position. as you see, some of the lines are now rendered incorrectly (the lines should join the boxes, like in the center of the image). note that the coordinates of the line vertices do not change between these two images, so i guess it is a more murky rendering issue that i cannot figure out.
any ideas?

perhaps it helps enabling the “render slicewise” pin in the Line-Node?

hi matias,

the Line (EX9.Geometry) is a pretty old node.
i think it came up when vvvv got shaders and more massive restructuration: around beta7.x
the Change Log sadly lacks this information.

Line (EX9.Geometry) is a little inconsistent:
it’s the only node of the category EX9.Geometry outputting a Layer instead of a Mesh. IMHO it would better fit into the category DX9 like the other primitives.
i assume that this is a “leftover” of the massive enhancements vvvv got in those days.

the behaviour you describe is known quite a while,
for “working around” you could try these:
*like sebl stated: “Render Slicewise”
*toggle “enable Depthbuffer” in Renderer just for a test
**if related to Depthbuffer you may try using ZWriteEnable (EX9.RenderState) . and not only on Line but also on other renderobjects.
maybe someone who is deeper into that 3D-chit can give better info here.

i also frequently experience the line node bugging out when vertices leave the view frustrum and/or come to lie behind the camera. don’t know any other possible solutions than kalle and sebl, but if nothing helps, you could work around this by using Rope (DX9) instead. the trick is to run your vertex coordinates through a ApplyTransform (Transform Vector) with the cameras’ ViewProjection-Transformation applied; you can then use the resulting xy-coordinates with the rope. you might need to adjust the Space pin to ‘ViewProjection’ or ‘Projection’ (or use WithinProjection (Transform) or similar).

(edit: that workaround might introduce other artifacts :P)

ropetrick.v4p (7.9 kB)

ah, thanks very much for replies!
in Line (EX9.Geometry) I don’t see the Draw Slicewise pin, like in some other DX9 nodes. depth buffer and ZWriteEnable did not help, and I tried the Clip render state as well, but diki’s rope trick seems to work fine! although, i am curious about the Space pin - it is present for this version in the Reference Rope (DX9), but not in my vvvv40beta21, even with a fresh install :o
should I be worried?

no need to worry, my memory and the documentation are not up to date on the issue :P the space pin on the dx9-nodes has been replaced by corresponding transform-nodes.