AtheneNoctua

Greetings! Took some time off this subject to cope with other challenges, but am back to pursuing it. I am going to try what you have come up with in the meantime and report on progress. Thanks much.

Just finished looking at the pyroclastic link and thinking about the possibility of doing the variations in VEX and got cautiously excited. The best part: Much of Apophysis code is written in Delphi. From what I can tell, Delphi is a close cousin to VEX already. The plugins are written in C or C++, so I'm assuming that they need to be fast. Pyroclastic noise: There is some confusion that "flame fractal" = "gaseous advection look" -- some of what I do has that look, and for those, serg's pyroclastic information is going to be phenomenally useful, once I wrap my head around it. "Wisps" use Perlin noise. That's one of the variations that I can use in Apophysis, but I actually don't use that one very often. Here is the source code for a variation I use more often than Perlin--Larry Berlin's "Foci_3D" variation. /* Apophysis Plugin This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ /* Modified by Larry Berlin September 2009 http://apophysisrevealed.com */ // Must define this structure before we include apoplugin.h typedef struct { } Variables; #include "apoplugin.h" // Set the name of this plugin APO_PLUGIN("foci_3D"); // Define the Variables APO_VARIABLES( ); // You must call the argument "vp". int PluginVarPrepare(Variation* vp) { // Always return TRUE. return TRUE; } // You must call the argument "vp". int PluginVarCalc(Variation* vp) { double expx = exp(FTx) * 0.5; double expnx = 0.25 / expx; double siny, cosy, sinz, cosz; double kikr, boot; boot = FTz; kikr = atan2(FTy,FTx); if(boot==0.0) { boot = kikr; } fsincos(FTy, &siny, &cosy); fsincos(boot, &sinz, &cosz); double tmp = VVAR / (expx + expnx - (cosy * cosz)); FPx += (expx - expnx) * tmp; FPy += siny * tmp; FPz += sinz * tmp; // Always return TRUE. return TRUE; } Which leads to another issue: Apophysis and its plugins are released under the GNU 2.0 and subsequent licenses. Which means that if/when I get all of this coded and working properly, I'm going to have to figure out where to upload it so the rest of you can get at it conveniently without breaking the terms of the license. Linkies for the curious: https://en.wikipedia.org/wiki/Apophysis_%28software%29 http://www.apophysis.org/ http://www.tmssoftware.com/site/scriptstudiopro.asp Another example of what I do besides what's in the teeny profile pic. It shows what you can do with the gradient-coloration system, when used on a wisp-type flame fractal. Since I haven't seen anything like this on any of the wisps or fractals I've found, I'm going to assume that coloring will be a research project on its own.

This book was written to be package-independent, I think. And the books and Siggraph presentations came out before Dreamworks released OpenVDB. If you follow along with the book, you compile a renderer, called pvr, and then use the python commands via bindings to send commands to the renderer. You're right in that I probably won't have to do C++, because Mr. Wrenninge has provided all that in GitHub at: https://github.com/pvrbook/pvr But-- If I'm going to be using Mantra instead of PVR and the HDK instead of Boost/SWIG, then absolutely it will be much simpler to learn the concepts. The catch for me is to figure out what in the HDK--heck, in the Houdini interface itself--corresponds to the book. Now that I think about it, they're ridiculously simple. Back then you evidently had to use python code to set motion blur, shutter angle, build a mesh (just did that this afternoon in the HDK--that was the first example in HDK: Getting Started). Or maybe just to use pvr. So I know I can set that up graphically in Houdini. Later on, the book's lessons get into Fractional Brownian Motion (fBm), octave gain, pyroclastic points, raymarchers, sparse grids yep, OpenVDB stuff)-- At this point, I'm guessing that my education is going to consist of going through the book, going through OpenVDB tutorials, seeing what information corresponds, and doing the happy-duck dance that I don't have to mess with installing 3rd-party libraries. After that, though, I'm going to have to do things like program the base fractal flame class, the base wisp class, and see how well the rendered results correspond to what I make in Apophysis. Next I will need to code the 20 variations in Yujie Shu's paper plus the others I've collected over the years (I have like about 200, now) and use hcustom or cmake to turn them into sops/plugins. Then I will have to figure out how to do the gradients. Wow. It all sounds almost possible now. Thanks. So... if you don't find anything in the above guesses that sound absolutely headdesk-ridiculous, maybe I'll finish the book, and who knows, start posting results in an "IFS Flame Fractal" thread in the Effects subforum sometime soon. Thanks for the help! (Sig made in Apophysis)

Hi, eetu, and thanks for pointing me to your flame test. The rest of the tests are exciting as well! Hmm. Since this is the Education subforum, I'd like to confine comments to one question. Then I'd like to make a general IFS Flame Fractal "Wisp" thread in the Effects forum, since a lot of people including myself seem to be very interested in the topic. (Yay!) On to Education. I've gone through some of Ari Danesh's tutorials and a general Bag of Holding-full of other random materials, so I think I've got enough to make a start. So here's the focus question, restated: How can I use what's already in Houdini and the HDK to follow along through Mr. Wrenninge's book? Because before I can participate with any intelligence in a general Houdini Wisp subforum, I need to get through that book. Here's the roadblock I'm working through (and will do so myself, given time): To go through the examples in the book, I need a python binding to C++ libraries that render volumetrically. Magnus Wrenninge thoughtfully uploaded PVR to GitHub, then uses the Boost.Python library to send commands which implement the examples in the book. Yujie Shu does the same thing, and she includes example code in her thesis (although mostly pseudocode), only she uses SWIG instead of Boost. I spent an entire week trying to install both of these, including bushels of other libraries (debugging, debugging, failing) until I decided to check to see if a python binding/wrapper/etc. had been already installed in Houdini. The hypothesis I now have is: I can use the HDK instead of Boost or SWIG just by opening a Python window in Houdini and merrily typing away at example code. Or not. Like if one of the example code lines is: for (boost::python::ssize_t i = don't_you_wish_you'd_installed_Boost_libraries_neener_neener) Anyway, as edward said, my next step is "Hello World" familiarity with what Houdini already has. I will report as soon as I've done this. By the way, Magnus Wrenninge has put up the first part of his book in free PDF form. This may give a better idea of what kind of education I am trying to put myself through, for whoever isn't sure. http://magnuswrenninge.com/content/pubs/ProductionVolumeRenderingFundamentals2011.pdf brb and thanks again.

Thank you so much for that advice! I'll dive in and hopefully have some progress to report (or most likely, more questions) But again, thanks.

Greetings-- I am an Apophysis IFS flame fractal artist and I'm trying to figure out how to do flame fractals (known to you as "wisps") in Houdini. In researching the possibilities, I came across Yujie Shu's Master's thesis "3D Fractal Flame Wisps" written at Clemson under Dr. Tessendorf. http://tigerprints.clemson.edu/all_theses/1704/ She and the thesis have been quite enlightening and I am grateful. I've snagged a copy of Magnus Wrenninge's book PRODUCTION VOLUME RENDERING: DESIGN AND IMPLEMENTATION and am trying to learn the concepts as I work through the book. While installing the libraries that Mr. Wrenninge notes at the beginning (frustrating process; learned a lot; would rather be making fractals than debugging), I noticed I'd been installing libraries that are already in Houdini. How can I use what's already in Houdini and the HDK to follow along through Mr. Wrenninge's book? Has anyone written instructions on how to do this? Also, as Yujie Shu has mentioned in her thesis, the coloration method in Apophysis is different from anything I've seen in Houdini yet (although admittedly I haven't seen much to date). The gradient coloration in Apophysis is a freaky-awesome system that uses chaos weights to adjust a sequence of 256 colors in a Fractint color map. If used adeptly, it can yield some spectacular results. Not least of which is that it creates results discernible to tetrachromats--those people who can see finer gradations of color than the rest of us can. (I think a few people so gifted have visited a couple of my art displays.) Has anybody tried to/succeeded in making a tool that would work in Houdini to use that system--Fractint color maps chaos-weighted Apophysis-style--in Houdini wisps? Thanks. PS: Let me know if this question needs a better forum to hide in.