Search found 382 matches

by spectral
Wed Mar 05, 2014 8:42 am
Forum: General Development
Topic: Measure the convergence speed
Replies: 20
Views: 14165

Measure the convergence speed

Hi, I'm currently looking for a way to measure the convergence speed. For now I use the FPS (frames per seconds) or SPS (samples per second), but it gives no information about the "pixel quality" ! I can have less FPS but better convergence ! So, how can I measure the image "error/delta" maybe compa...
by spectral
Thu Feb 27, 2014 8:03 am
Forum: General Development
Topic: Implementing a Shader System
Replies: 13
Views: 10477

Re: Implementing a Shader System

Hi, There are a lot of way to handle materials, by example : 1) uber shader You can just have one shader with a lot of parameters (see maxwell render by example) Then you can create several layers, each one having its own set of parameters. It is a good approach if you are able to create such materi...
by spectral
Wed Feb 26, 2014 5:03 pm
Forum: General Development
Topic: Curve bounding box - fast computation
Replies: 7
Views: 5055

Re: Curve bounding box - fast computation

But the convex hull property is really interesting on the other side :-D

Thanks
by spectral
Wed Feb 26, 2014 4:49 pm
Forum: General Development
Topic: Curve bounding box - fast computation
Replies: 7
Views: 5055

Re: Curve bounding box - fast computation

I have try using the following formulas : http://www.ibiblio.org/e-notes/Splines/Cardinal.htm

It seems to work, and so quick to compute... but the problem is that it is not really the minimum bounding box !

BTW, I will look at your paper right now... thanks
by spectral
Wed Feb 26, 2014 4:19 pm
Forum: General Development
Topic: Curve bounding box - fast computation
Replies: 7
Views: 5055

Re: Curve bounding box - fast computation

Thanks,

It looks promising.... so my question is now : how to convert my 4 control point of the cardinal curve to the 4 control points of the Bezier curve ? right ?

Have you any reference please ?
by spectral
Wed Feb 26, 2014 2:11 pm
Forum: General Development
Topic: Curve bounding box - fast computation
Replies: 7
Views: 5055

Curve bounding box - fast computation

Hi all, I'm currently looking for an approach to compute the bounding box of a cardinal curve (I use cardinal because the curve pass through the control points), in 2D ! You can look here for more explanations about the problem, and all the math stuffs : http://math.stackexchange.com/questions/69101...
by spectral
Fri Feb 14, 2014 6:57 am
Forum: General Development
Topic: Hair intersection : approaches ?
Replies: 16
Views: 13394

Re: Hair intersection : approaches ?

https://www.shadertoy.com/view/ldsGWB Here example of complex "not triangle" intersection test. Sure, it is nice and impressive... I have also think to use distance functions ( https://www.shadertoy.com/view/XsfGWN ), but the problem is that it require an accurate grid settings... it is not really ...
by spectral
Thu Feb 13, 2014 2:05 pm
Forum: General Development
Topic: Hair intersection : approaches ?
Replies: 16
Views: 13394

Re: Hair intersection : approaches ?

Thanks...

Also, looking for the following paper : "Real-Time Hair Modeling and Rendering using Ray Tracing on GPU: Introducing "Continual Cylinders" to represent hair"

If someone has a copy, he is welcome ;-)

Thanks
by spectral
Thu Feb 13, 2014 11:22 am
Forum: General Development
Topic: Hair intersection : approaches ?
Replies: 16
Views: 13394

Re: Hair intersection : approaches ?

Sure,

It is a way to setup the scene... even automatically. But, I'm not playing with LOD, simplification, etc... for now !

Just looking for some "ray - curve" intersection method ;-)

(Even for ribbons, faced planes, smooth cylinders etc...)

Thanks
by spectral
Thu Feb 13, 2014 10:19 am
Forum: General Development
Topic: Hair intersection : approaches ?
Replies: 16
Views: 13394

Re: Hair intersection : approaches ?

Thanks Dade, Yes I have see how you do in LuxRender, but it is not really of high quality if you zoom on the hairs... except if you tessalate a lot ! So, I'm looking at different approaches but also looking to directly compute the "curved mesh" ray intersection... by example, there is one paper "Ray...