Locking FG Map Issue

[nicknitro]

This is my first time posting on this website and I hope I come off as professional as possible to you guys .

 

I am currently a CG generalist in Lake Mary FL and have a bit of an issue I cant seem to resolve.

 

:Software 3ds Max 2009/Mental Ray:

 

I have a 360 turntable animation which I have baked out and resused a FG map to cut down on render time (front left back right frames). I had it rendering over the weekend over the network and what seems to happen is that I get black splotchyness on the object that my cameras rotating around a long with huge transitions in lighting (seems that FG turns off on some frames for some reason).

 

My Troubleshooting:

 

I turned off "Lock FG Map" so that it recalculates the map and the blotchyness goes away but as soon as I turn back on the "Lock FG Map" and the blotchyness comes back.

 

I broke the link between the Spec light rotating with my camera still same blotchyness.

 

Rewrote the FG map mutlitple times with different quality settings. Still when I turn on Lock FG map blotchyness, when I have it calculate the FG per frame...no blotchyness.

 

Any help or links would be GREATLY appreciated.

 

Thanks,

 

-Nick C

[postite]

Can we have a screenshot of the "black splotchyness"?

 

Perhaps you can try the radius interpolation method for your FG map. For exemple with max 20/ min 2.

[Justin Hunt]

Can we have a screenshot of the "black splotchyness"?

 

Perhaps you can try the radius interpolation method for your FG map. For exemple with max 20/ min 2.

 

Radius interpolation doesn't work for animations, but great for stills

 

jhv

[postite]

Radius interpolation doesn't work for animations, but great for stills

 

jhv

 

 

Ok, thx

Just tried it for stills.

[nicknitro]

Postite: Unfortunately I can not give you any screenshots for this is work for my job. It stinks because I know its hard to visualize what I'm trying to talk about.

 

Brian Bradley: Yes I chose 4 frames from my Render Cam that were front left back and right for my FG map to calculate from.

 

This is really stumping me and I have no idea right now how to go about fixing it ha.

 

Thank you all though for giving your input I really appreciate it.

[jinsley]

have you tried to animate the camera to pivot around the object? I have been doing some turntables where I have had to bake out textures:

 

1. I put a spiral around an object

 

2. animate the camera to follow the path

 

3. take FG points at intervals throughout the animation... like every 5 frames or whatever works

 

this seems to work pretty good...

[nicknitro]

Jinsley: I do have a circle spline around my object which my camera is bound to. This is all because I'm trying to save render time because Im using 3ds max's motion blur as well and that adds a good chunk of time onto each render. I will try and do it that way every n'th frame.

 

So every 5 or so frames should be good? Can I do that when rendering or should I bake out a FG map that has an interval of every 5 frames. Sorry kinda new to this.

 

Edit: Transformers RULE

[jinsley]

Jinsley: I do have a circle spline around my object which my camera is bound to. This is all because I'm trying to save render time because Im using 3ds max's motion blur as well and that adds a good chunk of time onto each render. I will try and do it that way every n'th frame.

 

So every 5 or so frames should be good? Can I do that when rendering or should I bake out a FG map that has an interval of every 5 frames. Sorry kinda new to this.

 

Edit: Transformers RULE

 

I would save the FG map first and then lock it. It might not have to be every 5th frame... you just want to make sure you are getting good coverage on the objects being rendered which might mean looping around the object twice from tow different hieghts... i have done some at 45 degree intervals = 8 frames needed and some at 18 degree intervals = 20 frames.

 

I said spiral, but I meant helix... sometimes I do more than one rotation and change the height of the camera as well so that on the second pass it is calculating from a different angle to get the spots it couldn't see on the first. I tend to get pretty good maps through this method.

 

This is just me though... someone like Brian or Justin might have some input into whether or not this is a good reason. I can't think of any reasons why it might not be.

[nicknitro]

Jinsley:

 

Thanks a bunch man I really appreciate it. Its just weird thought I dont know if its not getting enough FG points because I have the settings set to Very High (which is FG point density 4.0 Rays per FG point 10,000 Interpolate over Num. FG Points 100)

 

Its strange because Ill render one frame (front) where it calculates the FG points and no blotchy spot. Then Ill bake out the FG map on that same frame and lock it, then I get a blotchy spot.

[jinsley]

Jinsley:

 

Thanks a bunch man I really appreciate it. Its just weird thought I dont know if its not getting enough FG points because I have the settings set to Very High (which is FG point density 4.0 Rays per FG point 10,000 Interpolate over Num. FG Points 100)

 

Its strange because Ill render one frame (front) where it calculates the FG points and no blotchy spot. Then Ill bake out the FG map on that same frame and lock it, then I get a blotchy spot.

 

this might seem simple but have you reset the MR render engine? switch max to scanline, then switch back to MR. Those FG settings seem really high in my experience.

 

The most I have ever had to use was density 2, rays 500, and interpolate over 100 points.

 

Are you using GI as well?

[nicknitro]

No GI for. It does seem like overkill but we have a big scene scale so we have to use pretty big settings.

 

I dont think its MR because like I said when I have it calculate the FG map per render its fine but as soon as I Generate a FG map and lock it I get that splotchyness. I think you were right the first time in its how I am Generating my FG maps.

 

I really appreciate your help. I am learning a lot going through this. You never learn when everything goes right, its when things go wrong that you truly grow

[jinsley]

...You never learn when everything goes right, its when things go wrong that you truly grow

 

So true. How many bounces are you using for the FG?

[nicknitro]

I have 2 bounces right now. I turned it off just to see for some reason if that was the issue but it wasnt but was worth a shot ha.

 

I am rendering diagnostics right now for my FG map and it seems that where I am getting my blotchyness FG doesnt have a lot of points interpolating that area. Could this be the issue? That when I have those 4 FG frames its not interpolating it correctly?

[jinsley]

If you are only using FG I would say to try and start with at least 5 bounces. I don't think the FG is reaching as deep into the model as you need to distribute the light.

[jinsley]

a good reference for FG and how it works...

 

http://www.kxcad.net/autodesk/3ds_max/Autodesk_3ds_Max_9_Tutorials/tut_final_gather.html

[TSuess]

Nick,

 

Use the radius interpolation method. It will definitely get rid of the splotchy-ness. It will work for animation although you must recalculate FG for every frame. The photon map you can save and use everyframe.

[nicknitro]

Ok this is a really STUPID and Mind Numbing problem. Apparently it was the geometry that was causing FG to freak out. I dont think FG likes cones because at the tip of the cones it freaks out (even if a primitive cone is made) It gets blotchy at its tip.

 

So thats whats happened ha I thank you ALL for everything I love these forums and I will deff. be on here more and more for Max and MR info.

 

You guys are great thanks!

[jinsley]

glad its over and you figured it out. post some images when you can... I'm interested in seeing what was causing the problem.

[nicknitro]

Jinsley: Thanks man I appreciate your help. On your request Im sorry I can not post any images of my work because its for the company I work for and there are confidentiality agreements and its best I stick to them .

 

I will more then likely be working on my own sideprojects with Max and MR so when those problems arise I will deff show some images for everyone.

[jinsley]

I understand that, but when it goes public, if you can share that would be great. If not, no worries.

[nicknitro]

Sounds good. Hope to see you around the threads.