Planetside Software Forums

General => Terragen Discussion => Topic started by: Alf15000 on May 08, 2013, 06:16:07 AM

Title: Don't understand Twist and Shear's Base altitude
Post by: Alf15000 on May 08, 2013, 06:16:07 AM
Hi all !

I'm doing tests with Twist and Shear Shader, but I don't understand how base altitude works.

My example is a "pilar" based on a cube : (http://www.neoeon.net/Img_forums/orig.jpg)

I set Twist and Shear's Base Altitude at 0.5. I think that effect of this shader should be effective above half (0.5) of total altitude (200) like that (done with Photoshop) :  (http://www.neoeon.net/Img_forums/d.jpg)

Instead of this, I've got that : (http://www.neoeon.net/Img_forums/ba0.5.jpg)

So my question is : what is base altitude supposed to do ?

Thank you for answers :-)
Title: Re: Don't understand Twist and Shear's Base altitude
Post by: Tangled-Universe on May 08, 2013, 06:56:05 AM
I think it's the altitude from where the effect starts to kick in....what I know for certain is that it is in metres and not as a proportion as you thought.
(just think: how would this shader/node "know" that your tower is 200m tall? Or even more complex: how would such a proportion work on a terrain? I don't know)
Title: Re: Don't understand Twist and Shear's Base altitude
Post by: Dune on May 08, 2013, 07:13:03 AM
Just don't use it, but blend it by a distribution shader with a fuzzy zone, for smooth bends.
Title: Re: Don't understand Twist and Shear's Base altitude
Post by: Alf15000 on May 08, 2013, 07:35:04 AM
Thank you for your answers... I tried with meters, results are the same. And as Base altitude "range" is [0-1], I thought it was "in proportions".

I think about a distribution shader as Dune said, but I like to understand and I don't think Base altitude is only here for "decoration" ;-)
Title: Re: Don't understand Twist and Shear's Base altitude
Post by: Tangled-Universe on May 08, 2013, 07:52:35 AM
Well some settings are for decoration unfortunately.
Try the base altitude for strata&outcrops. I haven't been able to get it to work either.
Also in some occassions "fit blendshader" does nothing (it's unclear anyway what it really does).
Title: Re: Don't understand Twist and Shear's Base altitude
Post by: Alf15000 on May 08, 2013, 09:13:18 AM
Lol ! Same thing for me with Power Fractal's Adjust Coastline... It reassures me that I'm not the only Terragen 2 user's who have decoration settings :-)

However, it not really helps for understanding Terragen 2's settings that are already difficult to understand ;-)
Title: Re: Don't understand Twist and Shear's Base altitude
Post by: Dune on May 08, 2013, 12:27:33 PM
The latter does work, although I never use it.
Title: Re: Don't understand Twist and Shear's Base altitude
Post by: Alf15000 on May 08, 2013, 01:45:13 PM
Thank you Dune !  :)

I better understand Adjust Coastline ! That wasn't the subject of this topic, but it still helps me :-)
Title: Re: Don't understand Twist and Shear's Base altitude
Post by: paq on May 08, 2013, 09:04:58 PM
I have read somewhere the base altitude control the pivot position of the shear effect.
So basically it doesnt change the overall result of the effect.

At altutide 0%, the base postion dont move
At altutide 50%the base and top position move

The altitude as to be set in meter of course.




Title: Re: Don't understand Twist and Shear's Base altitude
Post by: Alf15000 on May 09, 2013, 02:50:46 AM
Excellent ! During my tests, I found that my "pilar" moved when base altitude changed, but I didn't managed to understand why his shape didn't change...

Your sketch is really understandable ! Thank you paq :)
Title: Re: Don't understand Twist and Shear's Base altitude
Post by: PabloMack on May 19, 2013, 10:09:30 AM
I think the base altitude may be the altitude above the planet sphere, not the altitude above the terrain's surface. Your "base" may be hidden below the terrain.
Title: Re: Don't understand Twist and Shear's Base altitude
Post by: Oshyan on May 29, 2013, 12:29:29 AM
Paq's diagram is correct. Nicely illustrated.

- Oshyan
Title: Re: Don't understand Twist and Shear's Base altitude
Post by: Ashley on January 10, 2015, 07:31:24 PM
Hi,

@Dune,
Would you be able to describe the node network for using the distribution shader to blend the twist and shear shader please.

I'm trying to create a pillar with a "Tim Burton-esque" curl to it.
So far I have a circle simple shape shader displaced with a smooth step.
I've tried using a merge shader but its not working out how I was expecting.

Cheers
Title: Re: Don't understand Twist and Shear's Base altitude
Post by: Dune on January 11, 2015, 03:41:26 AM
Check this out.
Title: Re: Don't understand Twist and Shear's Base altitude
Post by: Ashley on January 11, 2015, 06:17:42 PM
Thnx Dune,

I had a look, great to see an example of using the surface layer.
I edited the network to use only the first twist and shear and it was what I had in mind.