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Author Topic: Smooth transition between two MatIDs  (Read 497 times)

ShaneMcG

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Smooth transition between two MatIDs
« on: March 15, 2022, 09:01:06 AM »
Hi there,

I have a maybe easy question, but I'm trying to figure out the best way to do something in FP:



This is a very simplified model, just to get the point across. So, I want to use FP with grasses on the green areas and FP with gravel on the gray ones. Doing it using FP's Surface MatID option is a no-brainer. But what is the best way to achieve a jadded, smooth transition between the two FPs in the red area? The goal is, that the gravel slowly and smoothly 'dissolves' into the grass field.
(Please note, the area has now a 3rd MatID for visualisation purposes. In the end, the red areas are going to have the ID of the green areas.)
I'll attach the model for better understanding.

Thanks in advance for all your help and time!

ShaneMcG

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Re: Smooth transition between two MatIDs
« Reply #1 on: March 15, 2022, 09:04:15 AM »
Btw, here is what I am trying to achieve:


ShaneMcG

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Re: Smooth transition between two MatIDs
« Reply #2 on: March 15, 2022, 10:57:55 AM »
Update: That's how it looks like, when I try to achieve the goal, using Surface Mat ID scattering:



It's okay-ish, but I still need a smoother transition. A workaround I'll try is using a distance map. But maybe there is a smarter and more efficiant way?

Paul Roberts

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Re: Smooth transition between two MatIDs
« Reply #3 on: March 15, 2022, 10:58:52 AM »
That's an interesting question. I think because of the overlap your best bet is to use density and scale falloff curves. These aren't currently compatible with restricting a surface using material IDs, so instead I would create two spline areas that define the transition zone.



In the Forest Pack object the surface, click Select Objects and use only the grass models. Add the inner spline as an Exclude area. Next add the outer area as an Include spline. For this one, go to Select Objects again and pick only the gravel geometry.

You can now use Density and Scale falloff to gradually fade the two types of object as shown below.



I hope that helps, I've attached a sample file.

Note that you could also do this as two separate Forest Objects if you find that easier to manage. The same principles with the areas would apply.

Best,
Paul.
« Last Edit: March 15, 2022, 11:01:34 AM by Paul Roberts »
Paul Roberts
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Paul Roberts

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Re: Smooth transition between two MatIDs
« Reply #4 on: March 15, 2022, 11:22:26 AM »
Here's a quick preview of how it looks before and after this technique.

Paul Roberts
iToo Software

ShaneMcG

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Re: Smooth transition between two MatIDs
« Reply #5 on: March 15, 2022, 11:47:07 AM »
Dear Paul, thank you very, very much! I'll try it out and post the results.

ShaneMcG

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Re: Smooth transition between two MatIDs
« Reply #6 on: March 15, 2022, 12:58:05 PM »
Looking fine enough, I think:



Sure, the transition could be "wilder", but looking at the reference image, I think it's fine this way.
Thanks a lot once again!

Paul Roberts

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Re: Smooth transition between two MatIDs
« Reply #7 on: March 15, 2022, 01:01:53 PM »
Looking good! I think this question might make an interesting example for our next livestream.

Thanks,
Paul
Paul Roberts
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ShaneMcG

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Re: Smooth transition between two MatIDs
« Reply #8 on: March 15, 2022, 01:30:46 PM »
That would be awesome! Will be looking forward to it!
Is there a date already?

Paul Roberts

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Re: Smooth transition between two MatIDs
« Reply #9 on: March 15, 2022, 01:47:07 PM »
We're doing them on the last Thursday of every month, so for March it'll be the 31st.

Cheers,
Paul
Paul Roberts
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ShaneMcG

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Re: Smooth transition between two MatIDs
« Reply #10 on: March 31, 2022, 01:28:43 PM »
Hey Paul!

When does the livestream today take place?
I finished the project, that started this whole topic - here the results:















A ton of FP and even some RC have been used here! Thank you once again!

Paul Roberts

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Re: Smooth transition between two MatIDs
« Reply #11 on: March 31, 2022, 03:16:05 PM »
Hi,

Those renders look fantastic! Congratulations! Thanks for sharing them with us.

We're due to go live at 16:00 CET.

Cheers,
Paul
Paul Roberts
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amitgedia

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Re: Smooth transition between two MatIDs
« Reply #12 on: April 01, 2022, 09:48:52 AM »
Hi Paul,
When is the next stream in April and what time.

ShaneMcG

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Re: Smooth transition between two MatIDs
« Reply #13 on: April 01, 2022, 10:05:21 AM »
Hey there,

got a mail notification about your comment. I am not 100% sure of the specific date and time, but Paul said the livestreams are on the last Thursday of the month (which this April is going to be the 28.04.) and I guess the time remains the same - 16:00 CET.