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Old 02-18-2008   #1
Penjeet
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Default Help With Underwater Environmets DVD(Missing Section in Lecture 2)

Maya Dynamics Underwater Environments DVD problem with missing section in Lecture 2. This is the part I wanted most too for another scene I am working on.

I'm following along with lecture 2 on the dvd, near the end of the lecture the Instructor says he is going to show how to do sun beams that come down from the sky, then the lecture ends. When lesson 3 starts he's already got it done, and then moves on to the water fog lecture. I searched all over the dvd and cannot find any lesson that covers that section.


Anybody else notice this?...

and how do I do this section, I think I got it done mostly on my own, but I can't seem to get the light fog beams to penetrate the water surface and or fog.
I can see the beams rendered from above the water surface but once I go underwater they aren't visible anymore.


any help appreciated

Last edited by Penjeet; 02-18-2008 at 12:56 PM. Reason: Clarification
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Old 03-06-2008   #2
andy gee
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Hey

ok this I know the answer, that section on light beams was'nt included on the DVD. After a month of asking I got a mail from gnomon with the missing clip so here it is !! its too big to send, I will send it to you (via www.yousendit.com) What is your email address ??

If I am unable to send the section on this, this is what it says:

1. create a spot light and place it where the main sun light is. Point it in the direction of the sunlight so they match.

2. turn on light fog for the spot light, and using the scale tool make the size and length you want.

3. Click on the colour tab for the light and add the caustic pattern sequence for the colour.

4. under the image display click the use sequence box. Delete the expression which come in with it, set the first key to 1 and right click set key key, then set it to 150 and right click set key.

5. go to th graph editor and select frame 150 and go to curves post inifinity cycle.

6. light fog spread to 4. something, fog intensity to 1.5 and the light intensity to 1.5 prenumbra angle to something like 10.

and thats it.. if you want them to go through the water select the spot light, select your water, rendering tab, lighting/rendering, break light links

also I have discovered that the rays only render properly with maya software
mental ray only renders the outside of the cone not the inside, just a quick headsup.

hope this helps

Andy Gee

Last edited by andy gee; 03-06-2008 at 03:20 AM.
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Old 03-06-2008   #3
obocop
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Thumbs up Re: Light Fog

Andy, you beat me by an hour, but I was basically going to answer the same way. I actually figured it out myself once I looked up close on the DVD and saw the spotlight there. The only difference is that I mapped the image sequence into the fog intensity, rather than the colour. I tried that when I was stuffing around but it didn't work for me.

p.s. Andy, can you send me the link to that missing tut file too?
obocop at gmail.com
Thanks mate.

MY PROBLEM: SCHOOL OF SARDINES

This DVD is great but a lot of little things are either breezed over or left out. The bit that I am still stuck on is the bit on Lecture 9, to do with the school of sardines. I just can't get them to all go the same direction! - They all go along the motion path sideways. I've done it 3 times now, choosing the Instancer (Geometry Replacement) inside of sardine_particleShape and making AimDirection the worldVelocity option, but nothing happens, I just get "// Error: Too many arguments. Expected 1, found 2." error, and the sardines continue to swim sideways. When the instructor does it, he can't get it to work either, he says there it is a bug, refreshes his attribute editor and it works. How do you refresh your attribute editor like he does?
Has anyone else had this problem?

Last edited by obocop; 03-07-2008 at 19:22 PM.
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Old 03-06-2008   #4
andy gee
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Hey

I know what you mean. The DVD on underwater environments is great, but there are things that are breezed over also.

I dont know about the sardines situation but I did come up with a half decent looking water surface and that was'nt using the method show on the dvd.
I used a dielectric material on a nurbs plane, which was displaced by a 2D ocean shader.

Andy Gee
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Old 03-06-2008   #5
obocop
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Default Sardines

Finally worked it out. The instancer was working fine, it was just that my original sardine geometry that was being instanced had a different Y rotation. All I had to do was rotate it 90 degrees in Y so it was pointing a different direction and then freeze it's transformation. Now everything works fine.
Cheers for the reply Andy, i'll check out that ocean method soon.
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Old 03-25-2008   #6
andy gee
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Hey

Has anybody else had problems with the bubbles expression for the random rotation ?

The expression is :

Bubbles_LargeShape.Custom_RotatePP = rand(<<0,0,0>>,<<0,360,0>>);

only reason I ask is that when I add this expression my bubbles flip onto there side.

The expression doesnt work, and I was wondering if anybody has found a work around or solution to this ?

thanks

Andy Gee
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Old 03-26-2008   #7
obocop
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Default The Sun

Hey Andy,
Thanks so much for sending me that missing video file, much appreciated.

Not sure why your bubbles are doing that. I looked into my expressions and have the same expression and I THINK mine are working properly but then again it's so hard to tell with near spherical objects are rotating or not. I'll let you know if I think of anything.

On a separate topic, does anyone know how to create the look of the sun like they've got in this demo pic for this DVD? I'm just looking for the glowing ball effect, not the rays as they are discussed in the DVD. I've never had to create a sun before.
Thanks
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Old 03-26-2008   #8
andy gee
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Hey

In answer to your question.

You will have to render that out as a seperate layer using maya software.

Then composite on top of your colour layer later.

Mental ray does'nt render out opticle fx, but maya software does, so you'd have to render it seperately.

Also you'd have to setup some fresnel effect on the transparency of the ocean use a sampler info node then plug that into a ramp node with black at the bottom and white at the top, move them close together so you will produce the fresnel effect.

Then your opitcle effect will shine through the transparent areas of the water when the camera faces it.

I am using mental ray for my render at the moment so I am using render layers 1 has maya software which has opticle fx lense flare for this.

Hope this helps

( Also in regards to my question my bubbles flip when I add the expression to the bubbles. They go from facing upwards (after changing the aim direction to world velocity) back to how they look on my geometry on there side.

hope somebody can help.

Thanks

Andy Gee
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Old 03-28-2008   #9
obocop
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Default

Cheers Andy, i'll try to have a go at that fresnel effect. By the sounds of it, you're a bit more advanced a Maya user than I am, so I doubt I could be much use in your problem. I know i've seen the optical fx stuff in one of the menus but I cannot remember where. I've never even heard of a sampler info node, but I found it in the Hypershade so i'll give it a go.

I'm also using Mental Ray to render it and so far it looks pretty bad. I've got an IBL node (image based lighting) around my scene with a HDR image of a sky. So i'm using Global Illumination and Final Gather. Not sure if this is the best approach for this type of scene but i'm just using the techniques I learnt off the gnomon mental ray DVD. I've got a couple of directional lights in there but it doesn't look very natural to me. What would be the lighting set up you would use?

I'm also using render layers but i'm a beginner with them. I'm trying to get the bubbles, ocean and the sand particles to render as separate layers but to also exclude certain other objects. For example, I want to render the sandspash with the shape of the anchor excluded. I know it's possible because there's examples on the DVD in the Quicktime folder, in particular, bubble_example.mov and sandfloor_particle.mov that show it.

This project is driving me crazy. I spent so long on it and all would be solved if the DVD went through everything needed carefully, instead of leaving it's viewers with a partial result.

thanks in advance!
Owen
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Old 03-28-2008   #10
andy gee
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Hey obocop

My underwater scene, consist of an environmental lighting sphere. a couple of directional lights like you said. But I am using my own ocean made surface because the one that maya uses (maya ocean) although is great for scenes with from above isnt that realistic from below so I am using a nurbs plane displaced with a 2D ocean shader which has a mental ray dielectric shader applied to it.

The way I have my lighting setup is. That the environment sphere adds the general lighting via final gather, but I have also added a ramp texture node to the SKY HDRI colour gain tab. White in the middle of the ramp then followed by light blue then to dark.

this represents my horrison to underwater colour. So when I render where the white on the ramp is the sky HDRI will be shown and where the blues are on the ramp the underwater colour will be shown.

I have used the dielectric material instead of using the sampler info node like I mentioned I just get a better result I feel.

In regards to your render layers.

What I have done is for each layer if I have elements in the layer which I want the particles ie bubbles to interact with I applied them to the layer then simply added a matt black texture to them in that layer that way you get the interaction and then because its black, your compositer will read it as being cut out still leaving your other stuff in tact.

I have decided to render my bubbles with my colour layer because my bubbles are really close to the camera and sharks head so I want refractions etc... and I wont get that with a separate layer.

To sum up render layers are great for giving compositers great control over which parts of the animation does what or looks a certain way.

just remember if you have a sand particle element in your scene then in your render layer you will have to have the sand element, along withe the anchor which has a black matt material assigned to it etc..

Now if anybody can explain how to generate the fog layer that would be great.

sorry I cant help further, any other questions drop me a line

Andy Gee

Last edited by andy gee; 03-28-2008 at 09:01 AM.
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