Hi Ladies

I'm currently trying to design an asteroid.

I created the mesh with the rock generator from John "Evil Snack", see website:
https://www.geocities.ws/evilsnack/inc.htm

The result looks reasonably good, but improvements would be possible.
Maybe one of you has some ideas.

1. Dark triangles
Especially in movies you can see that it is built up of triangles.
First they are black, and less than a degree of rotation further they are
bright.
This may not be particularly noticeable in individual frames, but in movies it
is annoying.
I have already set the number of triangles very high, more is hardly possible.
Are there other ways to improve the mesh or other scripts to create it?

2. Textures
I've already played around with textures a bit, but I'm not completely
satisfied.
Does anyone have any textures for a similar use that they would like to share?

If the final result is presentable, I will of course publish it on my website
sooner or later.
Then others would also benefit from your ideas.

A short film is available here:
https://www.maetes.com/stuff/povray_forum_26_asteroid.mp4
8.4 MB, 24 seconds, 30 fps

Attached is a zip with my test environment, cropped to the bare minimum.
It can be executed via terminal with:
povray +Ies_generator_rock_examples_nano.pov +Otest/es_rock_nano_00.png +w1920
+h1080 -GR +A

Have a nice day,
Ma

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Attachments:
Download 'povray_maetes_asteroid_example.7z.zip' (2120 KB)

Here one of the results

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Attachments:
Download 'es_rock_00.png' (1257 KB)

Preview of image 'es_rock_00.png'

and another

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Attachments:
Download 'es_rock_nano_00.png' (457 KB)

Preview of image 'es_rock_nano_00.png'

Le 2026-07-29 à 07:33, Maetes a écrit :
> Hi Ladies
> 
> I'm currently trying to design an asteroid.
> 
> I created the mesh with the rock generator from John "Evil Snack", see website:
> https://www.geocities.ws/evilsnack/inc.htm
> 
> The result looks reasonably good, but improvements would be possible.
> Maybe one of you has some ideas.
> 
> 1. Dark triangles
> Especially in movies you can see that it is built up of triangles.
> First they are black, and less than a degree of rotation further they are
> bright.
> This may not be particularly noticeable in individual frames, but in movies it
> is annoying.
> I have already set the number of triangles very high, more is hardly possible.
> Are there other ways to improve the mesh or other scripts to create it?

Unavoidable when using meshes. Those dark/black triangles are just 
triangles that are physically facing away from the light, even if their 
normals are oriented toward the light.
Using an area_light with the area_illumination MAY help. Adjust the 
extent of the light until your results are acceptable. That area_light 
need to have the circular attribute. Be sure to use adaptive 0. Don't 
fear using something like 65x65, or more, for the number of elements. 
With adaptive 0, most of the time, only the corners will be evaluated.

> 
> 2. Textures
> I've already played around with textures a bit, but I'm not completely
> satisfied.
> Does anyone have any textures for a similar use that they would like to share?

As a lot of asteroids are really just big balls of gravel, some gravel 
based textures should be pretty realistic.

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On 29.07.2026 14:33, Maetes wrote:

> 2. Textures
> I've already played around with textures a bit, but I'm not completely
> satisfied.
> Does anyone have any textures for a similar use that they would like to share?
> 

I guess you can use Phobos and Deimos photos as some source for ideas. 
They are quite like asteroids but have more extensive portfolio.

In general, I suspect that slops and normals may disguise triangle 
flatness pretty well.

-- 
Ilyich the Toad
https://dnyarri.github.io/

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"Maetes" <nomail@nomail> wrote:

> 1. Dark triangles
.....
> Are there other ways to improve the mesh or other scripts to create it?

What if you used an isosurface? Then you could do away with triangles completely
and have "infinite resolution".


> 2. Textures
> I've already played around with textures a bit, but I'm not completely
> satisfied.

I'd just start searching the forums for rocks, asteroids, meteors, and any other
sort of concrete, brick, mortar textures.
Be sure to add normals to your object, and don't underestimate how strongly
lighting affects how things appear.

- BE

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On 29/07/2026 13:33, Maetes wrote:
> ...
> ...
> Are there other ways to improve the mesh or other scripts to create it?


By increasing the number of triangles and thus the accuracy ?

Two sets of macros that can be used for this :
* The New (and Improved!) Surface Subdivision Suite
* The Catmull-Clark Surface Subdivision Suite


On John's website :
<https://www.geocities.ws/evilsnack/index.htm#POVRAY>





-- 
kurtz le pirate
compagnie de la banquise

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kurtz le pirate <kur### [at] freefr> wrote:
> On 29/07/2026 13:33, Maetes wrote:
> > ...
> > Are there other ways to improve the mesh or other scripts to create it?
>
> By increasing the number of triangles and thus the accuracy ?

Yes, but as he stated in the sentence immediately prior:
"I have already set the number of triangles very high, more is hardly possible."

so it looks to me like he needs to move from a fixed geometry to an implicit or
interpolative one.

- BE

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On 31/07/2026 12:36, Bald Eagle wrote:
> kurtz le pirate <kur### [at] freefr> wrote:
>> On 29/07/2026 13:33, Maetes wrote:
>>> ...
>>> Are there other ways to improve the mesh or other scripts to create it?
>>
>> By increasing the number of triangles and thus the accuracy ?
> 
> Yes, but as he stated in the sentence immediately prior:
> "I have already set the number of triangles very high, more is hardly possible."
> 

I read it too quickly and it was poorly translated. Sorry.




-- 
kurtz le pirate
compagnie de la banquise

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I have little experience with Area Light so far, but maybe it's worth a try.
But the render time increases again.

I started with meshes because I found the rock generator and wanted to try it.
I would not have thought that you would see the triangles so well.

Here in the forum I found an isosurface asteroid and it actually looks quite
good, see picture.
Maybe I can improve it further, use it as an object in the foreground and
because of faster rendering time use the meshes for more distant objects.
https://news.povray.org/povray.binaries.images/thread/%3C449ebecf@news.povray.org%3E?mtop=10&moff=10

I also looked for textures, which I didn't find right away.
I came across this page that shows the built-in textures, very helpful.
https://povray.tashcorp.net/library/stones.inc/

This link
https://www.geocities.ws/evilsnack/index.htm#POVRAY
I have to take a closer look, looks like more training time.

Thanks for all the tips.

M

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Attachments:
Download 'es_rock_00.png' (442 KB)

Preview of image 'es_rock_00.png'