Chaos Corona Forum

Chaos Corona for 3ds Max => [Max] I need help! => Topic started by: Rhodesy on 2019-10-22, 13:10:56

Title: Straight vs Curved displacement map gradient ramp
Post by: Rhodesy on 2019-10-22, 13:10:56

Hi. We have a project where we need large areas of randomised tilted bricks on a curved surface - best shown in the attached test image. I've made the large randomised displacement map in omnitiles for photoshop with a single basic B/W gradient tile randomised out to fill a large area with a white grout mask. The effect is working well apart from the fact that Corona is interpreting the gradient as a curve rather than a straight line. I just cant think of a way of representing this gradient another way in photoshop so corona reads it as a straight ramp rather than curved. Is there anything I can do in corona to tell it to read it as a straight ramp? or do something different in PS?

Thanks 

Title: Re: Straight vs Curved displacement map gradient ramp
Post by: romullus on 2019-10-22, 14:23:19

(https://forum.corona-renderer.com/index.php?action=dlattach;topic=26595.0;attach=114247;image)

Title: Re: Straight vs Curved displacement map gradient ramp
Post by: Rhodesy on 2019-10-22, 14:40:39

Ha Ha, thanks. But I'm afraid I will need to be spoon fed. I cant work out how to change a bitmaps gamma to gamma 1.

Title: Re: Straight vs Curved displacement map gradient ramp
Post by: romullus on 2019-10-22, 14:47:52

When you load bitmap, select "override gamma" like this.

Title: Re: Straight vs Curved displacement map gradient ramp
Post by: Rhodesy on 2019-10-22, 14:48:37

Thanks again. I've just added a gamma of 0.454 in the colour correct shader and that seems to be helping things. I've been playing with gradient knots in Photoshop so I might need to go back to my original and see what happens. Thanks again.

Title: Re: Straight vs Curved displacement map gradient ramp
Post by: Rhodesy on 2019-10-22, 14:49:11

Ah just seen your post on the loader page - yes will do that.

Title: Re: Straight vs Curved displacement map gradient ramp
Post by: romullus on 2019-10-22, 14:55:45

Regarding photoshop part, IIRC by default photoshop's gradient isn't exactly linear, it adds some curve to it called "smoothing" or something like that, so you may want to remove it first. I can't tell you where to find it exactly, since i don't use photoshop anymore.

By the way, did you try Bercon tiles and Bercon gradient? They are perfect tools for such procedural bricks.

Title: Re: Straight vs Curved displacement map gradient ramp
Post by: Rhodesy on 2019-10-22, 15:08:38

Good intel. I've used the gradient smart filter set to linear but I can't see any further advanced options without digging further. In the mean time I'm pretty happy with the results now, especially as we wont be getting this close in the final image. Thanks again for your help.

Title: Re: Straight vs Curved displacement map gradient ramp
Post by: romullus on 2019-10-22, 15:42:43

You're welcome! Bricks looks straight to me, maybe defaults were changed in the more recent versions.