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MR: what's going on?


nisus
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Hi all,

 

I imported this model from max3.1 into max6.

Replaced the sunlight by a new one with the same settings as the import has converted the directional sun into an omni light. (I wonder why...)

 

AMS_0006_EV.jpg

 

So what's going on with the red, cyan, green and blue... Any clue?

 

I used all standard settings (from RTFM)... except I didn't use caustics... and no gathering (which makes the complete image a disco!)

 

rgds

 

nisus

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Hi Evert,

 

Can you give a few more details about your lighting setup? If GI is enabled, did you add anything to the scene after running a calc? Does using a material override make any difference? I think there are issues with mr and max's raytrace material, but I'm not sure if that's the case here.

 

Did you get one of those "obsolete data" messages on loading? Did you re-save?

 

Oh well, at least I'm someone to talk to until Alex wakes up. :)

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Hi Strat,

 

not yet, trying to get reasonable results (quality + time) on the demo for now...

 

Hi Fran,

 

Just some quick answers to your questions:

 

- Energy 200.000 (doens't make any different from the default although it should...) / GI photons: 100.000 / Caustics disabled / rest = default

(ow, I have the architectural MR setup running, so all objects are included in the GI and caustic calculations)

 

- I only added a sunlight (to replace the sun/omni). Next testruns will have the daylight system...

 

- I haven't changed any materials yet, so no override yet. The glass is a max raytrace material, so there could be a reason for the colored spots... although the grass is a standard material... I'll change the glass in the next test ;)

 

- obsolete data: always! (Normally some converting scale issues too... this time I was lucky not to have any)

 

rgds & tnx

 

nisus

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hi nisus. a similar thing happened to me last wed before i left for thanksgiving. i am just getting back to it now. i will probably just re-start with one of the previous saves before my file went corrupt, instead of trouble shooting what caused the problem.

 

however, if it helps, i am getting errors in my vray dialog box. the errors say:

 

warning: Material returned overbright or invalid color

 

not sure if this is a vray thing or a max thing.

 

filepush.asp?file=splotch.jpg

 

[ December 01, 2003, 07:20 AM: Message edited by: crazy homeless guy ]

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On the previous image I got this error:

photon emission shader returned miFALSE: aborting photon tracing

 

and when I change the glass with the mr-phenomenon i get...

max_Multimaterial' does not support material phenomenon

 

rgds

 

nisus

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Originally posted by nisus:

On the previous image I got this error:

photon emission shader returned miFALSE: aborting photon tracing

 

and when I change the glass with the mr-phenomenon i get...

max_Multimaterial' does not support material phenomenon

 

rgds

 

nisus

I think that means you can't use a phenomenon shader with a mult-subobject material. The quickest way to see if this is material-related is to set up a simple material - like the Arch. mat. Ideal Diffuse and drag it onto the material override button in the Processing tab of the render dialog. You need to recalculate the GI for an accurate evaluation.

 

You might want to create a sphere around your scene that encompasses your directional light (sun). Invert the normals and set it to receive GI and not to render in the object properties.

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Hi Fran,

 

I think that means you can't use a phenomenon shader with a mult-subobject material.
I figured this out too...

 

The quickest way to see if this is material-related is to set up a simple material - like the Arch. mat. Ideal Diffuse and drag it onto the material override button in the Processing tab of the render dialog.
What a wonderful tip! Haven't read about this one in the tutorials... Tnx a lot!

 

You need to recalculate the GI for an accurate evaluation.

I'm not sure whether I understand this... re-calculating a GI solution in MR? Can we save a solution? Thought that was only with radiosity...

 

You might want to create a sphere around your scene that encompasses your directional light (sun). Invert the normals and set it to receive GI and not to render in the object properties.
Sounds like another great tip... I'll try it after the material override. ;)

 

rgds & tnx a lot

 

nisus

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Nisus, something very similar to that used to happen with me in fr stage 1, after a lot of mistakes, i noticed that it was (at least in fr) a problem wuth the scale of the scene. See, if i had any object scaled, the samples go crazy and start to distribute in a very strange way, giving me that disco spots all around my scene. Dont know if it heps but, you can try this too. Be sure that if you scaled something, use "reset x-form" so that the object gets in 100% scale. It worked for me with fr.

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Hi Victor,

 

I had serieus issues with scale a week or so ago... I try not to rescale objects (all max manuals warn for this btw) but importing scenes sometimes force you to scale the file...

Don't know any good solution but not to import...

 

nisus

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Originally posted by nisus:

quote:
You need to recalculate the GI for an accurate evaluation.

I'm not sure whether I understand this... re-calculating a GI solution in MR? Can we save a solution? Thought that was only with radiosity...

nisus [/QB]In the "Photons (Caustics & GI)" section of the Indirect Illumination tab, there is an area called "Photon Map:", enable "Save" by clicking on the elipses button and giving a file name. Once you've calculated and saved a photon map, you enable "Load" in the same way, only selecting the photon map you created previously. I use the "Render" option just for quick tests when I don't want to overwrite a good calc.

 

The .pmap gets saved once the calculations are complete and rendering has started, not at the completion of the render.

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I've tried all tips so far (sphere, ideal diffuse material override). I realise now that my scene does not generate bounced light. I don't know why...

 

I've boosted Energy (x10 x20 x50 x100), GI photons (same amounts) without any visible difference between all images... Scale looks and measures correct...

 

AMS_0015_EV.jpg

 

 

Imho it has something to do with imported models. Any tests I've made in max6 generate bounced light, all imports fail. Any clue?

 

rgds

 

nisus

 

[ December 01, 2003, 03:25 PM: Message edited by: nisus ]

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It's not exactly the same, but the result is...

 

So far I got some improvements with a (heavy) gathering...

 

AMS_0022_EV.jpg

No Gather (no bounced light...)

 

 

AMS_0027_EV.jpg

With Gather (bounced light... but not too much - How do I make this stronger?)

 

 

Again Energy, Gi photons, GI Multipliers (of the sun) do NOT make any difference... (still wondering why...)

 

Anyone got a clue on what's going on?

Is it trouble with imported models?

 

rgds

 

nisus

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Hi, nisus.

 

You only have to use a few GI and Photon samples if you want to use FG in your solution. Say, 50 in the GI and Photons, but you have to pump up the FG samples to about 10x to 100x that amount.

 

Try setting the decay value of your sunlight or in the global light properties to 1.0 just to test if your light reaches its target before its dissipitates.

 

Again Energy, Gi photons, GI Multipliers (of the sun) do NOT make any difference... (still wondering why...)

Make sure you check enabled the rebuild option instead of reusing the cache when changing the params of your samples. Try tweaking your exposures too. :)
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Hi jucaro,

 

Tnx for the tips. Rendertime is now 1/5th only, (even with heavy gathering) but still the effect is not really visible.

 

Gonna try the decay...

 

Rebuild is on ;)

 

I don't understand what you mean by exposures (in MR?) Can you explain it a bit pls? Tnx

 

nisus

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Even though the default Radiosity is only supported in scanline, the exposure is supported in MR.

 

It's on the Render Scene dialog in the environment tab. For outdoor scenes, use logarithmic. But you can try automatic as well (and it'll work almost everytime, just don't use it for animation).

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Yep, that's the exposure thingy I meant.

 

I was trying recreate the effect of your first image post, although rigging an exterior scene in MR is quite easy, I could not figure what's causing it.

 

Here's my first few tries in MR.

GI & Photons set to 50 ang FG set to 500

MR Global light prop. Energy 50K, deacay 1.0 caustic 100 GI 100K

Logarithmic exposures enabled to 85,80,2.0,2000. check boxes unchecked

Rendering and calculation took about 5 mins.

 

hope this helps

filepush.asp?file=mrtest_1.jpg

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Any Final Render users have opinions about the big sphere idea? Just curious, as I've run into problems while rendering interiors with a large exterior in the bg.

 

Anyone have opinions about MR vs. the plugins? It's early on, but I am curious to see how people feel about them.

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MR has a GI max radius param wherein the user can set this value depending on scene extent. Enabling and setting this has the same effect as creating a sphere or dome to trap errant photons.

 

This image used a HDRI map for illumination. Took about 50 Photons in GI with a max radius value of 20m (scene extent) and 1000 samples in FG.

 

8 miniutes to calculate and render.

 

filepush.asp?file=mrtestHDRI.jpg

 

[ December 02, 2003, 08:22 AM: Message edited by: jucaro ]

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Originally posted by jucaro:

MR has a GI max radius param wherein the user can set this value depending on scene extent. Enabling and setting this has the same effect as creating a sphere or dome to trap errant photons.

Good point. cool2.gif
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