Timeshift inside for each loop is not working

Forums Technical Discussion Timeshift inside for each loop is not working

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MarXindia: Member; 34 posts; Joined: Sept. 2013; Offline

June 5, 2020 2:17 a.m.

Hi guys,

I am trying to reduce the polycount of the animated Houdini test geometry Crag.I tried to call each piece of Crag inside a for each loop and poly reduce it on a static frame using timeshift and later use poly deform to get the animation on my lowres model,but Timeshift is not working.I have attached the hip file here.

At a glance character seems to have optimized but,the flow is not working as intended.IF we change the frame from 109 to any other we can see that the paint is not sticking to the points because order is changing.

Also if there is any other way to obtain lowres animated geometry from such characters or assets,kindly let me know.

Kindly check and revert.

Edited by MarXindia - June 5, 2020 03:41:17

Attachments:
test_timeshift_inside_loop.hipnc (482.0 KB)


mrCatfish: Member; 731 posts; Joined: Dec. 2006; Offline

June 5, 2020 2:04 p.m.

You will need to unpack the geo to use it as a point deformer. I also moved the timeshift out of the loop, it's not necessary. You can actually lose the foreach loop entirely.

Edited by mrCatfish - June 5, 2020 14:05:55

Attachments:
Screenshot from 2020-06-05 14-03-20.png (40.8 KB)
SOLVERSOP_DELETE_RANDOMLY_OVER_TIME_catfish.hipnc (212.3 KB)

Sean Lewkiw
CG Supervisor
Machine FX - Cinesite MTL


MarXindia: Member; 34 posts; Joined: Sept. 2013; Offline

June 6, 2020 3:38 a.m.

mrCatfish
You will need to unpack the geo to use it as a point deformer. I also moved the timeshift out of the loop, it's not necessary. You can actually lose the foreach loop entirely.

Thanks for the response mrCatfish,and Sorry for being silly ignoring the unpack nodes.Actually my querry was regarding a studio asset
and I recreated this file using Crag since its sort of similar for the forum and forgot to add the unpack nodes.

Unfortunately this process doesnt work for me,yes this is working fine in case of crag.I have an studio asset char(so I cant bring it here) which is a rock char but is very high detailed and already has some intersections,when I followed this process I got the
result,but it had flickers while played and the point order kept changing,due to which paint textures donot stick,and that`s the reason I was trying to point deform individual pieces inside the loop.Kindly, let me know if you have any insights on this matter.

The Fx I am trying to achieve is generate particles based on intersection during characters movement in the knee and elbow area.


mrCatfish: Member; 731 posts; Joined: Dec. 2006; Offline

June 8, 2020 1:54 p.m.

This one works with the foreach loop. I think it is what you had, but you had forgotten the unpacks.

As for generating FX at intersections, I assume you are going to use boolean with seams detection?

Attachments:
test_timeshift_inside_loop_catfish2.hipnc (478.1 KB)

Sean Lewkiw
CG Supervisor
Machine FX - Cinesite MTL


MarXindia: Member; 34 posts; Joined: Sept. 2013; Offline

June 9, 2020 2:19 a.m.

mrCatfish
This one works with the foreach loop. I think it is what you had, but you had forgotten the unpacks.

As for generating FX at intersections, I assume you are going to use boolean with seams detection?

The file you attached is the perfect example of the issue that I am facing,If you look at the point count and hence the point numbers of the optimized geometry,they are changing,due to which the paint textures are not sticking.And this is where I am stuck.I have to create a setup for approx 40 shots, so I am looking for a straight forward approach which can give me triangulated and lowres animated geometry with static point count and order.

Regarding the Fx at intersections I was thinking of using intersection analysis,but if you can suggest other options it would be great.

Thanks

Edited by MarXindia - June 9, 2020 02:26:34

Attachments:
frame_74.JPG (60.4 KB)
frame_73.JPG (58.8 KB)


mrCatfish: Member; 731 posts; Joined: Dec. 2006; Offline

June 10, 2020 10:59 a.m.

Here is another approach that works, storing the original position in Cd and using that to deform the polyreduced geo.

Now that I think about it, timeshift and foreach is tricky. If you do a Google search you will see a lot of solutions to the problem, but it's addressed nicely on CG Wiki: https://www.tokeru.com/cgwiki/index.php?title=ForLoops#Loop_with_timeshift [www.tokeru.com]

Attachments:
test_timeshift_inside_loop_catfish6.hipnc (280.1 KB)

Sean Lewkiw
CG Supervisor
Machine FX - Cinesite MTL


MarXindia: Member; 34 posts; Joined: Sept. 2013; Offline

June 13, 2020 2:23 a.m.

mrCatfish
Here is another approach that works, storing the original position in Cd and using that to deform the polyreduced geo.

Now that I think about it, timeshift and foreach is tricky. If you do a Google search you will see a lot of solutions to the problem, but it's addressed nicely on CG Wiki: https://www.tokeru.com/cgwiki/index.php?title=ForLoops#Loop_with_timeshift [www.tokeru.com]

I got the issue,the problem was with the arrangement of geometry received from SHF.By default the pieces were not disassembling
properly.After working on that initial approach worked.

Thanks a lot for the help mrCatfish.I`ll look at Cd based approach.


NicTanghe: Member; 193 posts; Joined: Dec. 2016; Offline

Dec. 3, 2022 4:26 p.m.

Hello, I`m trying to use an animated camera and have a frustum everywhere it passes,
The timeshift node not working in a for each loop is making this verry hard to think through.

Anyone have any advise ?
currently I`m just manually placing it 10 times.


tamte: Member; 8555 posts; Joined: July 2007; Offline

Dec. 3, 2022 4:56 p.m.

NicTanghe
The timeshift node not working in a for each loop is making this verry hard to think through.

Time shift works in for each loop
Just use it on Block Begin node set to Input, not Piece or Feedback as those are cached

Tomas Slancik
FX Supervisor
Method Studios, NY


wyhinton1: Member; 61 posts; Joined: Feb. 2020; Offline

May 23, 2023 5:42 p.m.

tamte
NicTanghe
The timeshift node not working in a for each loop is making this verry hard to think through.
Time shift works in for each loop
Just use it on Block Begin node set to Input, not Piece or Feedback as those are cached

Worked for me thanks!!!

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