View Full Version : Errant texture projecting on another object

09-28-2012, 12:18 PM
Lightwave 11.0.3 x64, Windows 7

I've got a scene setup with a long single-sided flat polygon strip bent into a ring with a morph map, which has an image pasted on the Color channel and an alpha on the Transparency channel.

Behind that is a little cloud object, an extruded shape with an inset bevel with no offset just on the face.. effectively creating an outline for it:


As soon as I make the face of the cloud a little transparent, an undistorted piece of the texture on the ring object is getting applied onto the face of the cloud... or in this case multiple pieces, as the image map on the ring was set to Repeat:



Is this a bug or more of an 'undefined render behavior' given the fact that my extruded cloud object isn't double-sided polygons but the front inner face is transparent?

09-28-2012, 07:05 PM
Does the back face of your object have the same surface as the ring? I have been working with lightwave a long time and I am not aware of any render bugs that would cause a problem like this. Perhaps you could post the scene and object file.

09-29-2012, 09:40 AM
You might want to try checking/unchecking the V Stack option (Can't remember the exact wording) in the surface setting panel for that surface. I had some strange problems with image maps showing up in odd places on a project i just worked on and toggling that setting fixed the issue. The problem did not show up in the VPR but was there in the render.

10-03-2012, 04:47 PM
Thanks dw -- VStack indeed solved that problem! I've been searching around for a good explanation on what it means but haven't quite gotten it yet (it doesn't seem to be mentioned in the manuals at all..?)

10-03-2012, 05:53 PM
(it doesn't seem to be mentioned in the manuals at all..?)
....must....not.... snark.... ::sigh::

Please report the missing data to Fogbugz: I'm assured that it gets corrected quickly, but since updates are not to my knowledge made available.....

10-11-2012, 12:38 PM
Now I have a similar but different transparency issue...

I've got a bunch of 'pins on a globe' kind of thing; One object is the pin, and a separate object is a set of 3 nested spheres with enveloped transparency on each surface to make little sonar ring type things that emanate out when the pins appear on the map. These two objects are then cloned a whole bunch in the scene to place each individual pin.

However a bunch of these are really close to each other and the expanding sonar bits wind up intersecting each other. But when I render, the overlapping areas aren't transparent to one another, but act like they are transparent to just the background (I guess, it's hard to tell.) Played with the VStack switch on all the objects but it looks the same.

Any ideas on working around this one? Sample pic - Render is on the left, OpenGL in Layout screengrab on the right where you can see the clump of those pins and what the sonar things aught look like.


10-11-2012, 03:19 PM
Oooo, that's a good one.... :: pondering::... Raytracing your transparencies, right?

Well, not much help, but I suggest you create a simpler case where the problem might be easier to diagnose. Animate the bits to where they aren't intersecting, and then to where they are.

BTW, they aren't co-planar, are they?

10-12-2012, 02:11 AM
Yup, raytracing transparency, I turned off all shadows (cast/self-cast/receive) for them, excluded them from radiosity and even turned off radiosity as a test.. no help so far. They are tesselations with subdivision turned on, so that shouldn't be a problem.

Luckily I think I'm OK for this project, I'm bringing on the pins in sequence such that close ones only overlap minimally in time, and with other motion happening the errors aren't casually seen. But I'll strip the scene down to a straightforward example this weekend and post it for people to peek at and see if I'm just being stupid about something, and if not to submit to Fogz.

10-13-2012, 11:23 AM
Are the circular rings composed of single, overlapping polygons with texture maps and transparency involved? And are those polys intersecting once placed on the map such that a single poly might be above _and_ below another (think two planes intersecting in an "X" shape viewed from side) depending on where the intersection occurs? I've seen multiple, simultaneous cases of such arrangements can often cause issues. Cutting up the polys so a single poly is never both above and below any others in a small region sometimes helps, I've found, though can't necessarily be achieved when animation is involved.