violalyu Posted November 12, 2016 Share Posted November 12, 2016 Hi Houdini friends, Does anyone know how to use mask field in DOP net? I'm doing a simulation of leaves on the ground reacting to a car passing by. I need to control the wind force to affect only where the car is passing, where other leaves remains more still. Is there any way to mask out the affected area and have the wind force only affect that area and have dynamic change on the mask object? Or if there's other ways to do this? Thank you so much!!! Quote Link to comment Share on other sites More sharing options...
fencer Posted November 12, 2016 Share Posted November 12, 2016 check DOP_mask_field.hip 2 1 Quote Link to comment Share on other sites More sharing options...
Atom Posted November 12, 2016 Share Posted November 12, 2016 Cool, that is a nice example file. You can also plug the mask in to gravity, reverse the gravity direction and have particles rise up only when the box passes through them. Quote Link to comment Share on other sites More sharing options...
violalyu Posted November 12, 2016 Author Share Posted November 12, 2016 On 11/12/2016 at 1:44 PM, fencer said: check DOP_mask_field.hipFetching info... Expand Thanks Fencer! I've checked the file, I'll see if this setup will work in mine too! Quote Link to comment Share on other sites More sharing options...
violalyu Posted November 12, 2016 Author Share Posted November 12, 2016 On 11/12/2016 at 2:12 PM, Atom said: Cool, that is a nice example file. You can also plug the mask in to gravity, reverse the gravity direction and have particles rise up only when the box passes through them. Expand Thanks Atom, that's a nice idea! Quote Link to comment Share on other sites More sharing options...
violalyu Posted November 13, 2016 Author Share Posted November 13, 2016 On 11/12/2016 at 1:44 PM, fencer said: check DOP_mask_field.hipFetching info... Expand Hi fencer, I have another problem of this. After the leaves rise up they need to be not affected by the force anymore, but this method it continue to affect the leaves, so they never fall on the ground again. Is there any solution to that? Thanks!!! Quote Link to comment Share on other sites More sharing options...
Atom Posted November 13, 2016 Share Posted November 13, 2016 (edited) It seems to work for me, there is a gravity force following the wind. You do have to play with the numbers on the Wind Force. This GIF shows the windforce adjusted so the Scale Force is 6, was 60 and the Velocity in the Y-AXIS is 10, was 1. So the overall force is similar, 6 * 10 i.e. 60 but it is split between the input channels in a different way. Edited November 13, 2016 by Atom 1 Quote Link to comment Share on other sites More sharing options...
violalyu Posted November 13, 2016 Author Share Posted November 13, 2016 On 11/13/2016 at 10:18 PM, Atom said: It seems to work for me, there is a gravity force following the wind. You do have to play with the numbers on the Wind Force. This GIF shows the windforce adjusted so the Scale Force is 6, was 60 and the Velocity in the Y-AXIS is 10, was 1. So the overall force is similar, 6 * 10 i.e. 60 but it is split between the input channels in a different way. Expand Thanks Atom! I'll try this! Quote Link to comment Share on other sites More sharing options...
JDee Posted December 15, 2016 Share Posted December 15, 2016 (edited) Hey guys I'm trying to modify the fencer hip example by adding some noise into the box volume, so what I need is to make kind of noisy shape of the mask to affect the particles I simply put volumevop with some noise after the isooffset but all the setup is not working this way, the particles start moving out of the box mask. Does Sop Scalar Field allows me to do it basically ? thanks Edited December 15, 2016 by JDee Quote Link to comment Share on other sites More sharing options...
fencer Posted December 15, 2016 Share Posted December 15, 2016 On 12/15/2016 at 4:56 PM, JDee said: Hey guys I'm trying to modify the fencer hip example by adding some noise into the box volume, so what I need is to make kind of noisy shape of the mask to affect the particles I simply put volumevop with some noise after the isooffset but all the setup is not working this way, the particles start moving out of the box mask. Does Sop Scalar Field allows me to do it basically ? thanks Expand DOP_mask_field_v02.hip 1 Quote Link to comment Share on other sites More sharing options...
carloshs93 Posted March 11, 2020 Share Posted March 11, 2020 Still works on 2020 17.5 ;D thanks from the future 1 Quote Link to comment Share on other sites More sharing options...
Dubtronics Posted May 28, 2020 Share Posted May 28, 2020 Thanks guys this was really handy, I was also wondering how can we mask forces by other attributes. Say you wanted gravity only on particles that had reached a certain velocity. Quote Link to comment Share on other sites More sharing options...
oaschwab Posted September 11, 2020 Share Posted September 11, 2020 Is there a way to blur the mask so that it has a soft falloff? Quote Link to comment Share on other sites More sharing options...
fencer Posted October 5, 2020 Share Posted October 5, 2020 On 9/11/2020 at 1:52 AM, oaschwab said: Is there a way to blur the mask so that it has a soft falloff? Expand Sure, just multiply input volume values. Make gradien 0 to 1. Quote Link to comment Share on other sites More sharing options...
HM_2020 Posted February 6, 2023 Share Posted February 6, 2023 On 10/5/2020 at 9:04 PM, fencer said: Sure, just multiply input volume values. Make gradien 0 to 1. Expand Hey Fencer, cheers as always! Can you elaborate? Cheers! Quote Link to comment Share on other sites More sharing options...
fencer Posted February 6, 2023 Share Posted February 6, 2023 On 2/6/2023 at 12:16 PM, HM_2020 said: Hey Fencer, cheers as always! Can you elaborate? Cheers! Expand Volume mask has values 0 or 1, windforce reads this values as on/off state, if you remap volue from 0 to 1 you will have gradient falloff for windforce. DOP_mask_field_v03.hipFetching info... 1 Quote Link to comment Share on other sites More sharing options...
HM_2020 Posted February 8, 2023 Share Posted February 8, 2023 On 2/6/2023 at 4:29 PM, fencer said: Volume mask has values 0 or 1, windforce reads this values as on/off state, if you remap volue from 0 to 1 you will have gradient falloff for windforce. DOP_mask_field_v03.hip 280.61 kB · 6 downloads Expand Cheers for that, done anything with this method in the new FLIP SOPS? Quote Link to comment Share on other sites More sharing options...
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