Creating a Tire Spray from a Wetmap!!!

Forums Houdini Indie and Apprentice Creating a Tire Spray from a Wetmap!!!

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Shiv Dholakia: Member; 16 posts; Joined: July 2013; Offline

July 13, 2017 1:16 a.m.

Hi There,

I am trying to create a tire spray from a proxy vehicle that is rolling over a ground plane.

I have to use a wetmap(white is puddles, black is dry).

Please could you help me?

Thanks!

Regards,
Shiv

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Enivob: Member; 2630 posts; Joined: June 2008; Offline

July 13, 2017 9:04 a.m.

You can use an AttributeFromMap node to transfer the color from the image to a grid of points. Follow that up with a Delete that keeps only white points. Then you will have a set of points that match your map and can be used for particle emission.

Using Houdini Indie 20.0
Windows 11 64GB Ryzen 16 core.
nVidia 3050RTX 8BG RAM.


Shiv Dholakia: Member; 16 posts; Joined: July 2013; Offline

July 13, 2017 10:17 a.m.

Enivob
You can use an AttributeFromMap node to transfer the color from the image to a grid of points. Follow that up with a Delete that keeps only white points. Then you will have a set of points that match your map and can be used for particle emission.

Thanks a lot for the response, it is much appreciated!

I am attaching a scene file and the wet-map, please could you show me a practical working example using it?

I am a relatively new Houdini user.

Thank you, I would be very grateful.

Regards,
Shiv

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Edited by Shiv Dholakia - July 13, 2017 14:15:04

Attachments:
wetmap.jpg (87.6 KB)
test_fx.hip (230.4 KB)


Shiv Dholakia: Member; 16 posts; Joined: July 2013; Offline

July 14, 2017 5:32 p.m.

Hi,

Please could someone help me with a practical example and a scene file?

My scene file is appended above.

I don't know how to transfer the color to a grid of points and use them as particle emission.

I am a very new user.

Regards,
Shiv

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Edited by Shiv Dholakia - July 15, 2017 06:06:53


Shiv Dholakia: Member; 16 posts; Joined: July 2013; Offline

July 16, 2017 1:42 a.m.

Just pinging to get this sorted out by anybody here. Thanks!


Enivob: Member; 2630 posts; Joined: June 2008; Offline

July 16, 2017 9:55 a.m.

Check out this thread on OdForum. You can also search there for more tire based efffects. You may have to become a user to download the example files.

http://forums.odforce.net/topic/27279-particles-behind-car-tires/#comment-157806 [forums.odforce.net]

Edited by Enivob - July 16, 2017 09:55:40

Using Houdini Indie 20.0
Windows 11 64GB Ryzen 16 core.
nVidia 3050RTX 8BG RAM.


Shiv Dholakia: Member; 16 posts; Joined: July 2013; Offline

July 16, 2017 6:07 p.m.

Enivob
Check out this thread on OdForum. You can also search there for more tire based efffects. You may have to become a user to download the example files.

http://forums.odforce.net/topic/27279-particles-behind-car-tires/#comment-157806 [forums.odforce.net]

Thanks a lot for pointing me to the right direction, I appreciate it!

While this is really helpful, it doesn't solve the issue of emitting only on the white(puddle) areas of the wetmap. I want a transition of the spray to no p=or less spray from the white to black areas of the wetmap.

The other issue I am having is right now the spray particles move with the car as if they were parented to it.

Not sure how to isolate the particle transform with that of the car's. The car is getting animated on a path at scene level.

Attaching a new scene file with this problem.

Thanks again!

Edited by Shiv Dholakia - July 17, 2017 14:11:13

Attachments:
sd_carSpray_v001.hipnc (393.7 KB)


Shiv Dholakia: Member; 16 posts; Joined: July 2013; Offline

July 16, 2017 9:47 p.m.

Posted another update above with new scene file.


Enivob: Member; 2630 posts; Joined: June 2008; Offline

July 18, 2017 1:20 p.m.

I rebuilt the scene using your car geometry and the points you generated from the tire. I took the shelf tool approach instead of placing everything in one node. You can use the Y Variance on the PopSource to cause the particles to kick up a little higher. Adjust particle life to determine the length of the trail.

Edited by Enivob - July 18, 2017 13:22:43

Attachments:
car_tire_particles.gif (391.7 KB)
ap_car_tires_particles.hipnc (413.5 KB)

Using Houdini Indie 20.0
Windows 11 64GB Ryzen 16 core.
nVidia 3050RTX 8BG RAM.


Shiv Dholakia: Member; 16 posts; Joined: July 2013; Offline

July 18, 2017 7:21 p.m.

Enivob
I rebuilt the scene using your car geometry and the points you generated from the tire. I took the shelf tool approach instead of placing everything in one node. You can use the Y Variance on the PopSource to cause the particles to kick up a little higher. Adjust particle life to determine the length of the trail.

Thanks so much, I greatly appreciate it and am grateful for all your help!

This FX task is now solved.

I used attributeFromMap node in conjunction with scatter and delete nodes to generate a grid of points from the white colored areas of the UV map and deleted the non-white points using a range expression.

The result is now it only splashes where there are white points.

Edited by Shiv Dholakia - July 18, 2017 19:30:24


DarrianBenford: Member; 1 posts; Joined: July 2018; Offline

Aug. 11, 2018 11:44 a.m.

I am having this same trouble I am confused about the attribfrommap part and just the whole project overall

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