Re: Test inside geometry failing

[Ciaran Moloney]

Cool!
I always wanted to add the ray intersect test to make this thing more
robust, but have long since run out of energy...

Ciaran

On Wed, May 8, 2013 at 1:14 AM, Eric Thivierge wrote:

>  Thanks guys,
>
> Ciaran, your addon actually works exceptionally well in my case. The
> slider for the "Override_test_distance" gets rid of the errant areas very
> very well. Not to mention generating this particle cloud is super fast now.
> You've saved me some late night work today. :)
>
> I did try to roll my own but was still getting the unwanted areas. The
> tips on how to build it are appreciated as it may help in future cases.
>
> Cheers,
>
>
> Eric Thivierge
> ===
> Character TD / RnD
> Hybride Technologies
>
>
> On 07/05/2013 7:23 PM, Ciaran Moloney wrote:
>
> IIRC implementing the ray intersect technique is problematic in ICE, since
> the raycast node only returns the first intersection. You'd have to
> manually shoot subsequent rays after every hit.
>
>
>
> On Wed, May 8, 2013 at 12:06 AM, Raffaele Fragapane <
> raffsxsil...@googlemail.com> wrote:
>
>>   You could write/wire the test yourself.
>>  Point inside hull is fairly trivial outside of fringe cases, shoot a ray
>> in any direction, if it intersects an odd number of times, it's outside,
>> even, it's inside.
>> You might want multiple rays and take the median of the result, or work
>> conservatively and flag it even if just one tests true.
>>
>>  You can further refine this with a force field approach, run a distance
>> from hull (closest location on geo), and if the point is close enough to a
>> location with a normal facing away from its distance vector remove it, and
>> remove anything within a certain threshold (very close) indiscriminately.
>>
>>  Testing against denser geometry also helps, even if it's more expensive,
>> sparse and variedly populated topology tends to introduce more room for
>> error.
>>  Lastly, a triangulated mesh, especially if you have a certain degree of
>> dis-planarity in your geo on large enough areas, will also improve things
>> in my experience.
>>
>>
>>
>> On Wed, May 8, 2013 at 4:54 AM, Eric Thivierge wrote:
>>
>>> Anyone notice how many times this just doesn't work correctly? Even
>>> toggling the Closed volume inside often doesn't give the correct results as
>>> well...
>>>
>>> I have a voxel setup with particles and testing inside a geometry to
>>> keep the ones that are within, works, however there are many points still
>>> outside the geo that remain and aren't deleted. The ones left outside
>>> changes each frame as well.
>>>
>>> Anyone have any sure fire methods / workarounds that don't involve
>>> having helper nulls to delete the remaining ones outside?
>>>
>>> --
>>> Eric Thivierge
>>> ===
>>> Character TD / RnD
>>> Hybride Technologies
>>>
>>>
>>>
>>
>>
>>  --
>> Our users will know fear and cower before our software! Ship it! Ship it
>> and let them flee like the dogs they are!
>>
>
>
>

Re: Test inside geometry failing

[Eric Thivierge]

Thanks guys,

Ciaran, your addon actually works exceptionally well in my case. The 
slider for the "Override_test_distance" gets rid of the errant areas 
very very well. Not to mention generating this particle cloud is super 
fast now. You've saved me some late night work today. :)


I did try to roll my own but was still getting the unwanted areas. The 
tips on how to build it are appreciated as it may help in future cases.


Cheers,

Eric Thivierge
===
Character TD / RnD
Hybride Technologies

On 07/05/2013 7:23 PM, Ciaran Moloney wrote:
IIRC implementing the ray intersect technique is problematic in ICE, 
since the raycast node only returns the first intersection. You'd have 
to manually shoot subsequent rays after every hit.




On Wed, May 8, 2013 at 12:06 AM, Raffaele Fragapane 
mailto:raffsxsil...@googlemail.com>> wrote:


You could write/wire the test yourself.
Point inside hull is fairly trivial outside of fringe cases, shoot
a ray in any direction, if it intersects an odd number of times,
it's outside, even, it's inside.
You might want multiple rays and take the median of the result, or
work conservatively and flag it even if just one tests true.

You can further refine this with a force field approach, run a
distance from hull (closest location on geo), and if the point is
close enough to a location with a normal facing away from its
distance vector remove it, and remove anything within a certain
threshold (very close) indiscriminately.

Testing against denser geometry also helps, even if it's more
expensive, sparse and variedly populated topology tends to
introduce more room for error.
Lastly, a triangulated mesh, especially if you have a certain
degree of dis-planarity in your geo on large enough areas, will
also improve things in my experience.



On Wed, May 8, 2013 at 4:54 AM, Eric Thivierge
mailto:ethivie...@hybride.com>> wrote:

Anyone notice how many times this just doesn't work correctly?
Even toggling the Closed volume inside often doesn't give the
correct results as well...

I have a voxel setup with particles and testing inside a
geometry to keep the ones that are within, works, however
there are many points still outside the geo that remain and
aren't deleted. The ones left outside changes each frame as well.

Anyone have any sure fire methods / workarounds that don't
involve having helper nulls to delete the remaining ones outside?

-- 
Eric Thivierge

===
Character TD / RnD
Hybride Technologies





-- 
Our users will know fear and cower before our software! Ship it!

Ship it and let them flee like the dogs they are!

Re: Test inside geometry failing

[Ciaran Moloney]

IIRC implementing the ray intersect technique is problematic in ICE, since
the raycast node only returns the first intersection. You'd have to
manually shoot subsequent rays after every hit.



On Wed, May 8, 2013 at 12:06 AM, Raffaele Fragapane <
raffsxsil...@googlemail.com> wrote:

> You could write/wire the test yourself.
> Point inside hull is fairly trivial outside of fringe cases, shoot a ray
> in any direction, if it intersects an odd number of times, it's outside,
> even, it's inside.
> You might want multiple rays and take the median of the result, or work
> conservatively and flag it even if just one tests true.
>
> You can further refine this with a force field approach, run a distance
> from hull (closest location on geo), and if the point is close enough to a
> location with a normal facing away from its distance vector remove it, and
> remove anything within a certain threshold (very close) indiscriminately.
>
> Testing against denser geometry also helps, even if it's more expensive,
> sparse and variedly populated topology tends to introduce more room for
> error.
> Lastly, a triangulated mesh, especially if you have a certain degree of
> dis-planarity in your geo on large enough areas, will also improve things
> in my experience.
>
>
>
> On Wed, May 8, 2013 at 4:54 AM, Eric Thivierge wrote:
>
>> Anyone notice how many times this just doesn't work correctly? Even
>> toggling the Closed volume inside often doesn't give the correct results as
>> well...
>>
>> I have a voxel setup with particles and testing inside a geometry to keep
>> the ones that are within, works, however there are many points still
>> outside the geo that remain and aren't deleted. The ones left outside
>> changes each frame as well.
>>
>> Anyone have any sure fire methods / workarounds that don't involve having
>> helper nulls to delete the remaining ones outside?
>>
>> --
>> Eric Thivierge
>> ===
>> Character TD / RnD
>> Hybride Technologies
>>
>>
>>
>
>
> --
> Our users will know fear and cower before our software! Ship it! Ship it
> and let them flee like the dogs they are!
>

Re: Test inside geometry failing

[Raffaele Fragapane]

ARGHH, as usual, no proof reading is as good as the one done after sending.
Even = outside
Odd = inside.


On Wed, May 8, 2013 at 9:06 AM, Raffaele Fragapane <
raffsxsil...@googlemail.com> wrote:

> You could write/wire the test yourself.
> Point inside hull is fairly trivial outside of fringe cases, shoot a ray
> in any direction, if it intersects an odd number of times, it's outside,
> even, it's inside.
> You might want multiple rays and take the median of the result, or work
> conservatively and flag it even if just one tests true.
>
> You can further refine this with a force field approach, run a distance
> from hull (closest location on geo), and if the point is close enough to a
> location with a normal facing away from its distance vector remove it, and
> remove anything within a certain threshold (very close) indiscriminately.
>
> Testing against denser geometry also helps, even if it's more expensive,
> sparse and variedly populated topology tends to introduce more room for
> error.
> Lastly, a triangulated mesh, especially if you have a certain degree of
> dis-planarity in your geo on large enough areas, will also improve things
> in my experience.
>
>
>
> On Wed, May 8, 2013 at 4:54 AM, Eric Thivierge wrote:
>
>> Anyone notice how many times this just doesn't work correctly? Even
>> toggling the Closed volume inside often doesn't give the correct results as
>> well...
>>
>> I have a voxel setup with particles and testing inside a geometry to keep
>> the ones that are within, works, however there are many points still
>> outside the geo that remain and aren't deleted. The ones left outside
>> changes each frame as well.
>>
>> Anyone have any sure fire methods / workarounds that don't involve having
>> helper nulls to delete the remaining ones outside?
>>
>> --
>> Eric Thivierge
>> ===
>> Character TD / RnD
>> Hybride Technologies
>>
>>
>>
>
>
> --
> Our users will know fear and cower before our software! Ship it! Ship it
> and let them flee like the dogs they are!
>



-- 
Our users will know fear and cower before our software! Ship it! Ship it
and let them flee like the dogs they are!

Re: Test inside geometry failing

[Raffaele Fragapane]

You could write/wire the test yourself.
Point inside hull is fairly trivial outside of fringe cases, shoot a ray in
any direction, if it intersects an odd number of times, it's outside, even,
it's inside.
You might want multiple rays and take the median of the result, or work
conservatively and flag it even if just one tests true.

You can further refine this with a force field approach, run a distance
from hull (closest location on geo), and if the point is close enough to a
location with a normal facing away from its distance vector remove it, and
remove anything within a certain threshold (very close) indiscriminately.

Testing against denser geometry also helps, even if it's more expensive,
sparse and variedly populated topology tends to introduce more room for
error.
Lastly, a triangulated mesh, especially if you have a certain degree of
dis-planarity in your geo on large enough areas, will also improve things
in my experience.



On Wed, May 8, 2013 at 4:54 AM, Eric Thivierge wrote:

> Anyone notice how many times this just doesn't work correctly? Even
> toggling the Closed volume inside often doesn't give the correct results as
> well...
>
> I have a voxel setup with particles and testing inside a geometry to keep
> the ones that are within, works, however there are many points still
> outside the geo that remain and aren't deleted. The ones left outside
> changes each frame as well.
>
> Anyone have any sure fire methods / workarounds that don't involve having
> helper nulls to delete the remaining ones outside?
>
> --
> Eric Thivierge
> ===
> Character TD / RnD
> Hybride Technologies
>
>
>


-- 
Our users will know fear and cower before our software! Ship it! Ship it
and let them flee like the dogs they are!

Re: Test inside geometry failing

[Ciaran Moloney]

On Tue, May 7, 2013 at 8:37 PM, Steven Caron  wrote:

> maybe instead of just doing it in houdini he could use SDFs?
>
> http://blog.blackredking.org/?p=47
>

Yeah, that'll also fail on complex shapes...

Often, subdividing the geometry will fix the problem.

Re: Test inside geometry failing

[Steven Caron]

maybe instead of just doing it in houdini he could use SDFs?

http://blog.blackredking.org/?p=47


On Tue, May 7, 2013 at 12:34 PM, Peter Agg  wrote:

> Yeah, that's my only suggestion really - I've had quite a few problems
> before where I had very dense particles being culled by complex geo and on
> random frames you'd get very distinct cubes where the volume calculations
> have freaked out. Never found a particularly useful workaround, I'm afraid.
>
> Simplifying the geo has helped, sometimes not grouping them together and
> doing several tests on individual parts did. But sometimes that just shifts
> the problem to different frames - for the project I was on we had one of
> those unfortunate 'just do it in Houdini' moments.
>
> Good luck! :)
>
>
> On 7 May 2013 20:29, Eric Thivierge  wrote:
>
>>  Not necessarily cubes. If I run a smooth op on the geo it fixes much of
>> it (although this is not a solution for me) so it's got to be the internal
>> methods not liking something about the geometry.
>>
>>
>> Eric Thivierge
>> ===
>> Character TD / RnD
>> Hybride Technologies
>>
>>
>> On 07/05/2013 3:26 PM, Peter Agg wrote:
>>
>> Is this the thing where you get giant cubes of bad volume data, or
>> something else?
>>
>>
>> On 7 May 2013 19:54, Eric Thivierge  wrote:
>>
>>> Anyone notice how many times this just doesn't work correctly? Even
>>> toggling the Closed volume inside often doesn't give the correct results as
>>> well...
>>>
>>> I have a voxel setup with particles and testing inside a geometry to
>>> keep the ones that are within, works, however there are many points still
>>> outside the geo that remain and aren't deleted. The ones left outside
>>> changes each frame as well.
>>>
>>> Anyone have any sure fire methods / workarounds that don't involve
>>> having helper nulls to delete the remaining ones outside?
>>>
>>> --
>>> Eric Thivierge
>>> ===
>>> Character TD / RnD
>>> Hybride Technologies
>>>
>>>
>>>
>>
>>
>

Re: Test inside geometry failing

[Peter Agg]

Yeah, that's my only suggestion really - I've had quite a few problems
before where I had very dense particles being culled by complex geo and on
random frames you'd get very distinct cubes where the volume calculations
have freaked out. Never found a particularly useful workaround, I'm afraid.

Simplifying the geo has helped, sometimes not grouping them together and
doing several tests on individual parts did. But sometimes that just shifts
the problem to different frames - for the project I was on we had one of
those unfortunate 'just do it in Houdini' moments.

Good luck! :)


On 7 May 2013 20:29, Eric Thivierge  wrote:

>  Not necessarily cubes. If I run a smooth op on the geo it fixes much of
> it (although this is not a solution for me) so it's got to be the internal
> methods not liking something about the geometry.
>
>
> Eric Thivierge
> ===
> Character TD / RnD
> Hybride Technologies
>
>
> On 07/05/2013 3:26 PM, Peter Agg wrote:
>
> Is this the thing where you get giant cubes of bad volume data, or
> something else?
>
>
> On 7 May 2013 19:54, Eric Thivierge  wrote:
>
>> Anyone notice how many times this just doesn't work correctly? Even
>> toggling the Closed volume inside often doesn't give the correct results as
>> well...
>>
>> I have a voxel setup with particles and testing inside a geometry to keep
>> the ones that are within, works, however there are many points still
>> outside the geo that remain and aren't deleted. The ones left outside
>> changes each frame as well.
>>
>> Anyone have any sure fire methods / workarounds that don't involve having
>> helper nulls to delete the remaining ones outside?
>>
>> --
>> Eric Thivierge
>> ===
>> Character TD / RnD
>> Hybride Technologies
>>
>>
>>
>
>

Re: Test inside geometry failing

[Eric Thivierge]

Not necessarily cubes. If I run a smooth op on the geo it fixes much of 
it (although this is not a solution for me) so it's got to be the 
internal methods not liking something about the geometry.


Eric Thivierge
===
Character TD / RnD
Hybride Technologies

On 07/05/2013 3:26 PM, Peter Agg wrote:
Is this the thing where you get giant cubes of bad volume data, or 
something else?



On 7 May 2013 19:54, Eric Thivierge > wrote:


Anyone notice how many times this just doesn't work correctly?
Even toggling the Closed volume inside often doesn't give the
correct results as well...

I have a voxel setup with particles and testing inside a geometry
to keep the ones that are within, works, however there are many
points still outside the geo that remain and aren't deleted. The
ones left outside changes each frame as well.

Anyone have any sure fire methods / workarounds that don't involve
having helper nulls to delete the remaining ones outside?

-- 
Eric Thivierge

===
Character TD / RnD
Hybride Technologies

Re: Test inside geometry failing

[Peter Agg]

Is this the thing where you get giant cubes of bad volume data, or
something else?


On 7 May 2013 19:54, Eric Thivierge  wrote:

> Anyone notice how many times this just doesn't work correctly? Even
> toggling the Closed volume inside often doesn't give the correct results as
> well...
>
> I have a voxel setup with particles and testing inside a geometry to keep
> the ones that are within, works, however there are many points still
> outside the geo that remain and aren't deleted. The ones left outside
> changes each frame as well.
>
> Anyone have any sure fire methods / workarounds that don't involve having
> helper nulls to delete the remaining ones outside?
>
> --
> Eric Thivierge
> ===
> Character TD / RnD
> Hybride Technologies
>
>
>

Test inside geometry failing

[Eric Thivierge]

Anyone notice how many times this just doesn't work correctly? Even 
toggling the Closed volume inside often doesn't give the correct results 
as well...


I have a voxel setup with particles and testing inside a geometry to 
keep the ones that are within, works, however there are many points 
still outside the geo that remain and aren't deleted. The ones left 
outside changes each frame as well.


Anyone have any sure fire methods / workarounds that don't involve 
having helper nulls to delete the remaining ones outside?


--
Eric Thivierge
===
Character TD / RnD
Hybride Technologies