CGTalk - Mental Ray and Skybox

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DrPretorius

11-21-2008, 05:11 PM

Hi All,

I posted this in the wrong forum section (CG General Discussion), so I have reposted it here as requested, I hop this is OK.

This is my first time here, and my first question.

I have made a scene in max 2009, Talos from Jason and the Argonauts myth, using the Daylight system, and I have used a skybox because there is a camera movement, the problem is that the skybox comes out as just black, everything else is lit ok, I have even made the light exclude the skybox from shadows, no matter what I do it is always black.

UPDATE:

Thanks to The Neverman and Visionmaster2 for there replies, and to answer there questions, yes Final Gather was on, and no, mr skylight was not selected in the skylight rollout, but is now, and now can see the skybox, but it seems to be a blur, I have a detailed cloud sky texture here, but can not see this, could it be the skybox is too big?, also in the Sunlight option of the Daylight parameter standard is selected.

I have included a smallish render of what I am upto, so you can see what I mean about the sky being blured. The camera moves towards Talos then stops, then Talos animates and gets off the base, WIP by the way.

cheers

aydinu

11-22-2008, 06:37 AM

Just a thought: Did you flip the normals of the skybox?

Aydin

Abraham

11-22-2008, 09:07 AM

Try and check in the bitmap parameters your blur settings, max defaults to 1, try to change that to 0.1 to see if it fixes your problem :)

j-L

DrPretorius

11-22-2008, 07:10 PM

Hi,

Thanks for your replies, no the normals are not flipped, as the skybox shows up as a blur, I tried the blur ratio on the materials and this did not work..:(, if I do the render with out a light sorce and in scanline render the skybox appears dandy and clear, so something with my mental ray set up?.

Also how do I post a image, as I uploaded a image of the render, but can not see it.

ta.

Abraham

11-22-2008, 07:39 PM

I think, you can't really upload an image (I might be wrong) but you can use a free image hosting provider (I use http://imageshack.us/ ) A picture will really help to see the problem better, I agree :)

J-L

DrPretorius

11-22-2008, 09:14 PM

Hi, here is the link to the render

http://img518.imageshack.us/img518/6782/talosyy4.jpg

Thanks.

DrPretorius

12-16-2008, 02:24 PM

Well I have not touched it for a while, but I can not seem to solve the problem, I even changed the texture to a brick texture, just to see what happens, and it comes out the same blurred blue, just like the image, I have done everything that has been said here with no luck..

:(

MikeBracken

12-17-2008, 12:25 AM

I think what you are seeing is the MR Sky. The normals should be facing the camera in order to see the image applied to the box. Try flipping the normals.
What type of material are you using on the box ?

Regards,
Mike

DrPretorius

12-17-2008, 01:46 PM

I think your right, it is the MR Sky that is just being seen. The normals are flipped, I am using a normal bitmap material on the skybox.

I know I can add a image i:e clouds as well as Mr Sky, but I need the skybox as the camera moves.

cheers

MikeBracken

12-17-2008, 02:26 PM

What I would do in your situation is to make a "mentalray" material, and put your bitmap into the sufrace slot. You can then change the brightness by changing the output amount in the bitmap perameters rollout. If I am not using the gamma settings in the Max preferences, I also add a gamma/gain utility to the bitmap to keep it from getting washed out.
I always render my sky out as a seperate pass, but I usually need it in the scene for reflections. So I just uncheck "visible to camera" in the object properties of the sky dome/box. Then, of course, remove the MR sky shader from the env slot.
If you can seperate the sky pass, you will get more control in post for color correcting, etc.

Regards,
Mike

DrPretorius

12-18-2008, 09:59 AM

Thanks Mike, I am a bit busy at the mo, so when I get back to it I will let you know of the results.

cheers

Mysterious-03

12-21-2008, 07:13 PM

hi
i have one problem wiht mental ray
when i use daylight than i want to add in my scene another light (mr omni) and with daylight it's don't work and not lighing, please help me
Thank

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