Thomas de Groot <tho### [at] degrootorg> wrote:
> It is understandable as one does not want to have overlapping objects,
> but the force moving them apart seems too strong to me, and cannot be
> controlled by hand unfortunately.
>

It makes for some fantastic explosions, though ;)

> With random objects, the difficulty is to have them as close in shape as
> possible to the basic collision objects. That puts some constrains upon
> the modelling...
>

There are many cases in which mesh/collision-shape inconsistencies aren't too
noticeable, if the objects are grouped together somehow.

For example, the attached is a test using compound collision objects in Blender.
A cylinder (head) and cone (tip) were parented to a cylindrical shaft. Each was
given a collision bounding method to automatically match its respective
geometry.

To makes things easier on myself (and also due to upgrading to the new version)
I wrote an addon for Blender which directly exports transformations of all
selected objects to an .inc file, so it's now possible to go straight from
Blender to POV-Ray. It seems like the simplest way to accomplish things,
especially considering all the nice tools that are available in Blender.

Sam

Post a reply to this message

Attachments:
Download 'nails.jpg' (115 KB)

Preview of image 'nails.jpg'

"Samuel Benge" <stb### [at] hotmailcom> wrote:
> For example, the attached is a test using compound collision objects in Blender.

Wow, very nice! I have almost no experience using Blender.

> I wrote an addon for Blender which directly exports transformations of all
> selected objects to an .inc file, so it's now possible to go straight from
> Blender to POV-Ray. It seems like the simplest way to accomplish things,
> especially considering all the nice tools that are available in Blender.

That's really cool too; I guess it's time to DL the new version myself and check
it out.

As a simple example of going "direct" I grabbed this sim screenshot of the most
basic demo in the Bullet SDK and then appended the resulting POV-Ray image.

-------------------------------------------------
www.McGregorFineArt.com

Post a reply to this message

Attachments:
Download 'bulletbasicdemo.jpg' (381 KB)

Preview of image 'bulletbasicdemo.jpg'

"Robert McGregor" <rob### [at] mcgregorfineartcom> wrote:
> As a simple example of going "direct" I grabbed this sim screenshot of the most
> basic demo in the Bullet SDK and then appended the resulting POV-Ray image.

Here's a textured version :)
-------------------------------------------------
www.McGregorFineArt.com

Post a reply to this message

Attachments:
Download 'bulletbasicdemotextured.jpg' (654 KB)

Preview of image 'bulletbasicdemotextured.jpg'

"Robert McGregor" <rob### [at] mcgregorfineartcom> wrote:
> "Samuel Benge" <stb### [at] hotmailcom> wrote:
> > For example, the attached is a test using compound collision objects in Blender.
>
> Wow, very nice! I have almost no experience using Blender.

Thanks!

It's not the easiest program to use at first. Things are hidden and not very
obvious, but they become clear soon enough.

> > I wrote an addon for Blender which directly exports transformations of all
> > selected objects to an .inc file, so it's now possible to go straight from
> > Blender to POV-Ray. It seems like the simplest way to accomplish things,
> > especially considering all the nice tools that are available in Blender.
>
> That's really cool too; I guess it's time to DL the new version myself and check
> it out.

You really should. This new version is so much better than, say, 2.49.
Everything's so much easier now, and the things it can do... it's an amazing
program, although it does have its quirks :)

If you do DL it, you might try out the exporter addon I just uploaded to
p.b.misc:
http://news.povray.org/povray.binaries.misc/thread/%3Cweb.5056a911b09798c46664708b0%40news.povray.org%3E/

> As a simple example of going "direct" I grabbed this sim screenshot of the most
> basic demo in the Bullet SDK and then appended the resulting POV-Ray image.

Nice. How "direct" are we talking?

Attached is another test, this time showing a ball blasting through a wall of
cubes. For the motion blur effect, I saved two states of the sim at different
time steps and interpolated the transformations in POV over a series of frames.
The images were then averaged together.

Sam

Post a reply to this message

Attachments:
Download 'wall-shot-b.jpg' (88 KB)

Preview of image 'wall-shot-b.jpg'

On 16-9-2012 21:21, Samuel Benge wrote:
> Thomas de Groot <tho### [at] degrootorg> wrote:
>> It is understandable as one does not want to have overlapping objects,
>> but the force moving them apart seems too strong to me, and cannot be
>> controlled by hand unfortunately.
>>
>
> It makes for some fantastic explosions, though ;)

Absolutely!

> [...]
> To makes things easier on myself (and also due to upgrading to the new version)
> I wrote an addon for Blender which directly exports transformations of all
> selected objects to an .inc file, so it's now possible to go straight from
> Blender to POV-Ray. It seems like the simplest way to accomplish things,
> especially considering all the nice tools that are available in Blender.

One more reason for me to continue learning Blender! I find the program 
much easier now than some versions ago when I just abandoned it.

 From what I see, the end result of the physics animation is much better 
(with objects) than what Poser Physics does (its ragdoll animation is 
good). Somehow I remain with objects not touching each other and 
floating in space within a bowl (See image; Poser render). The objects 
fall very rapidly into position and then remain thus for the rest of the 
animation, even after about a thousand frames.

Thomas

Post a reply to this message

Attachments:
Download 'poserphysicstest.png' (276 KB)

Preview of image 'poserphysicstest.png'

"Samuel Benge" <stb### [at] hotmailcom> wrote:
> "Robert McGregor" <rob### [at] mcgregorfineartcom> wrote:
> > "Samuel Benge" <stb### [at] hotmailcom> wrote:

> If you do DL it, you might try out the exporter addon I just uploaded to
> p.b.misc:
>
http://news.povray.org/povray.binaries.misc/thread/%3Cweb.5056a911b09798c46664708b0%40news.povray.org%3E/

Thanks Sam, will do!

> > As a simple example of going "direct" I grabbed this sim screenshot of the most
> > basic demo in the Bullet SDK and then appended the resulting POV-Ray image.
>
> Nice. How "direct" are we talking?

Very direct; I just added an export function to the Bullet basic demo app to
write the POV-Ray include file.

> Attached is another test, this time showing a ball blasting through a wall of
> cubes. For the motion blur effect, I saved two states of the sim at different
> time steps and interpolated the transformations in POV over a series of frames.
> The images were then averaged together.

That motion blur effect is outstanding! How many frames did you average to
achieve this shot?

-------------------------------------------------
www.McGregorFineArt.com

Post a reply to this message

Thomas de Groot <tho### [at] degrootorg> wrote:
>  From what I see, the end result of the physics animation is much better
> (with objects) than what Poser Physics does (its ragdoll animation is
> good). Somehow I remain with objects not touching each other and
> floating in space within a bowl (See image; Poser render). The objects
> fall very rapidly into position and then remain thus for the rest of the
> animation, even after about a thousand frames.

It looks like the collision shapes just aren't corresponding to the actual
geometry closely enough. Is a hull or mesh collision shape available in Poser
Physics?
-------------------------------------------------
www.McGregorFineArt.com

Post a reply to this message

Thomas de Groot <tho### [at] degrootorg> wrote:
> Somehow I remain with objects not touching each other and
> floating in space within a bowl (See image; Poser render).

Nuts! Is there any sort of padding setting for colliding objects? I mean, do the
objects try to keep a distance from other objects to avoid errors?

Another thing that occurs to me (although I haven't used Poser since around
1999) is that you are using displacement maps for your objects. Perhaps Poser is
using the /unmodified/ meshes for collisions, not the modified versions. That
would cause some spacing issues for sure.

> The objects fall very rapidly into position and then remain
> thus for the rest of the animation, even after about a thousand frames.

I'm guessing the objects are "sleeping" too soon after settling. Is there a "no
sleeping" or similar option you can disable?

Sam

Post a reply to this message

"Robert McGregor" <rob### [at] mcgregorfineartcom> wrote:
> "Samuel Benge" <stb### [at] hotmailcom> wrote:
> > Attached is another test, this time showing a ball blasting through a wall of
> > cubes. For the motion blur effect, I saved two states of the sim at different
> > time steps and interpolated the transformations in POV over a series of frames.
> > The images were then averaged together.
>
> That motion blur effect is outstanding! How many frames did you average to
> achieve this shot?

Forty, though it looks like fewer because I jittered the camera's position at
each frame for antialiasing/focal blur. All frames together finished rendering
in about 4 minutes 45 seconds using three 2.4GHz cores, which isn't too bad at
all. Radiosity and area_light settings were low, everything got a scaled-down
bumps normal, and no AA was used.

On a related subject, I noticed that POV-Ray's actual focal blur uses the same
set of samples for each frame. I'm guessing this is due to the Halton sequence
used, but is very annoying when trying to have very low focal blur settings with
the intention of averaging frames together. If each frame used a different
sample set, you could get away with a blur_samples value of 1, which as far as I
can tell, adds nothing to the render time. It would be nice to have the option
of using random focal blur samples for each frame :)

Sam

Post a reply to this message

To Robert:
I think that is the case indeed. Poser Physics uses Ball, Box, and 
Capsule (a cylinder with rounded ends), and Ragdoll as collision 
objects. While I couple each mesh to one of the collision objects, it 
seems that the mesh has to be exactly conform, so no initial transform 
to it should be done, or that is what I guess presently.

To Sam:
No, there is no padding setting.
My meshes are /pure/ meshes; however see my answer to Robert.
There is no sleeping option available.

I want to do the same with only collision objects and see what happens 
but I believe that there is a serious constrain on Poser Physics... :-(

Thomas

Post a reply to this message