Nebula

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Nebula

Postby DK » Wed May 15, 2019 9:05 am

Anyone got any ideas on how to make an effective Nebula in Moho?
None of the brushes seem up to the job.

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Re: Nebula

Postby slowtiger » Wed May 15, 2019 10:36 am

(Well, if this isn't the job for a bitmap program?)

Which kind of nebula do you think of, which amount of detail? For total realism I'd use a NASA photo, they're all free to use.

Does it need to change/evolve? How about stars? I could think of solutions with two or three self-made brushes.
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Re: Nebula

Postby DK » Wed May 15, 2019 10:46 am

Hi Slow.
I would like to try and keep it to vectors for printing in different resolutions......I have had some success and quite like the results of this one.

EDIT: I need to do about 10 different shapes.

Image

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Re: Nebula

Postby slowtiger » Wed May 15, 2019 1:01 pm

Ah, that's what I'd call a galaxy.

Uhm, if you use brushes you're already using bitmaps. And since they're quite small (up to 512x512px) you shouldn't print them larger than 2 inches.

Your example made me think. These irregular borders ... what about vectorising some splattery immage, and use this as mask, combined with various blurred shapes? (Putting several layerrs inside a group and make this a mask is one of Moho's biggest assets.)

The stars could easily be built in Moho, I remember doing it some years ago. Some combination of a circle with radial gradient, plus a cross made from same circle inside a 4 point star mask. But you need this only for larger stars, the smaller stuff is just circles with a bit of blur.

Again you may vectorize some image with a lot of points and make this one shape, to minimize processor load.
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Re: Nebula

Postby Greenlaw » Wed May 15, 2019 5:38 pm

Here's a cheap trick that's worked for me even in live-action movies I've worked on...

Paint a circular spiraling image in a square canvas, then map that to a layer. If you're using an existing photo, reshape it to fit a square space. Then rotate the image on its z axis to spin it 360 degrees so you can cycle it. Now place this inside another group and rotate that back on its x axis. This will give the 'nebula/galaxy' or whatever some perspective and depth. If you want to cheat more depth, you can transform this group using any of the transforming tools.

You might want to key out the background or set it to comp with the additive or screen blend mode.

If you want to give it a little more life, use a mesh warp to slowly expand the 'arms' of the image while is't spinning. This will be easier to do if you mute the channels for the parent group first.

If you're more ambitious, try adding multiple layers of different 'spirals' and time the rotations for each layer a little slower or faster. You'll probably want to comp these with screen or additive blend settings.

I normally do this sort of thing in AE, Fusion, or LightWave but it should work in Moho too.

Hope this helps.
Last edited by Greenlaw on Fri May 17, 2019 12:54 am, edited 1 time in total.
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Re: Nebula

Postby DK » Thu May 16, 2019 12:00 am

Thanks Slow and Greenlaw.
Yes Slow. The imagery I need is of Galaxies not Nebulas.
I actually tried using a brush to mask the rings in Moho but I couldn't get enough irregularity around the edges so I used a more detailed vector brush in CorelDraw to mask out the rings. Still not 100 percent happy but it will do the job. I will try your cheap trick suggestion Greenlaw and see how it comes up it Moho.

Cheers and thanks!
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Re: Nebula

Postby Greenlaw » Thu May 16, 2019 3:47 pm

Here's a super quick example I threw together this morning using some found images:

Image

The image in the upper left is the original image and the spinning one is the image reshaped and mapped to an angled layer--which makes it look more like the original photo but now it can spin correctly.

I've attached the project files so you can pick it apart.

GalaxySpin.zip

If I was doing this effect for real, I'd use a mesh warp or some kind of vortex warp that make the inside region spin a little faster so the outside stars will appear to trail or drag a little. I'd probably layer some more stuff too.

Hope this helps.
Last edited by Greenlaw on Fri May 17, 2019 12:58 am, edited 2 times in total.
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Re: Nebula

Postby DK » Fri May 17, 2019 12:40 am

Wow.
That is really cool Greenlaw! Thanks for posting the file too.
It does look way better as a raster image I must agree.


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Re: Nebula

Postby DK » Fri May 17, 2019 12:57 am

Greenlaw. I have a question re: your file?
The GalaxyXfmd_zRot.png (Galaxy Image) is above the maxresdefault.jpg (Stars Background Image) in the moho layer setup.
There appears to be no Alpha channel in the GalaxyXfmd_zRot.png or any masking set yet in the gif above, you can see the background stars of the maxresdefault.jpg through the GalaxyXfmd_zRot.png. Am I (more than likely) missing something?

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Re: Nebula

Postby Greenlaw » Fri May 17, 2019 1:03 am

Yes, alpha is not necessary in this case because the spinning element's Blend mode is set to Additive in the Layer settings. When the background of the foreground image is black, any pixels underneath the layer that's brighter will show through. (With Additive, brighter pixels will always add to black, so black is technically 'invisible'.)

When Additive adds up too much and the image gets blown out, try using Screen instead.
Last edited by Greenlaw on Fri May 17, 2019 1:11 am, edited 2 times in total.
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Re: Nebula

Postby DK » Fri May 17, 2019 1:06 am

Hi Greelaw. Brilliant. I keep forgetting about the blend modes :) I tried the masking tool and it's pretty good at deleting most of the black as well especially for a space scene like this .

Cheers and thanks again for the help and advice.
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Re: Nebula

Postby Greenlaw » Fri May 17, 2019 1:07 am

Oops, I didn't completely answer your question. To see the Additive effect, you need to render the image.

Maybe someday we'll get a proper live preview for Blend modes.
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