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View Full Version : Image World HRDI Pinching



riki
09-25-2004, 07:00 PM
I've got a simple reflective object moving around on a flat ground. I've also added a HDR in Image World to give it something to reflect. The problem though, as the object spins and moves, the relections start to pinch and warp and looks pretty ugly at different stages of the animation. Is there anyway to fix this?

faulknermano
09-25-2004, 10:17 PM
do you think that pinching is caused by the image itself, since, after all, it is mapped spherically? if so, you may try other mapping methods, but the downside is that you may have to raytrace. or alternately, (if your image map was not originally spherically projected) reproject it spherically in hdrshop... well that would depend how the image looks like actually.....

riki
09-25-2004, 10:47 PM
I always get this problem it doesn't seem to mater what image I use. Here's a screenshot to give a better idea. The other problem is that I'm on a Mac so not able to use HDRShop and Gimp doesn't really seem to be working properly on the Mac yet. I also never use radiosity, becuase my G4 just can't handle it. I'm guessing that if the image was a seemless tile it might solve the problem, possibly not though. I need to do run some tests.

But I'm guessing that other people must run across this problem all the time.

faulknermano
09-25-2004, 10:59 PM
I always get this problem it doesn't seem to mater what image I use. .


well, for sure, if you use just any image you will get this pinching because, from what i see in your attached image, there is a pole where it pinches. this denotes the spherical mapping distortion i mentioned. you have to use a spherically projected image to avoid the poles. i can offer three advices:

1.) change the axis of imageworld so that the camera doesnt "see' the pole.

1.) do not use image world.. instead project your image out on a box (it seems your image is made for planar mapping). use planar or cubic mapping.

2.) convert your image 'spherically.' i'm not sure how to accurately do this in lw. i do it hdrshop. the problem is the pinch. you can try this, but not sure if it works (just the first thing on my mind): create a sphere. create a spherical UV map for it. in layout use a cylindrical projection of your image. dont use the UV map, though. just project it normally. and then bake the surface using the spherical UV map you just created. i'm thinking that the cylindrical projection will give less distortion than a standard spherical one.

riki
09-25-2004, 11:16 PM
Thanks faulknermano, I'll try some of those options, and see how I go.