cs00bren Posted January 6, 2003 Share Posted January 6, 2003 i'm trying to create a landscape scene but i'm having problems with the trees i've tryed l-systems but i've found it to processor intensive. to place them i instances them to a particle system. so the question any good ideas or any tutorials out they. cheers bren. Quote Link to comment Share on other sites More sharing options...
sirogi Posted January 6, 2003 Share Posted January 6, 2003 You could try modelling a library of good looking trees with L-systems, write those to disk, and then copy stamp them through file SOPs on your particles... tip o' the iceberg... Cheers... Quote Link to comment Share on other sites More sharing options...
stu Posted January 6, 2003 Share Posted January 6, 2003 Another trick is to just model the branches and trunk and create the leaves by modelling a rough volume representing the volume that you want to fill with leaves and birth particles to that volume at frame 1. Then you can copy a super simple leaf model to the particles with a somewhat random rotation that can be animated over time to simulate wind. stu Quote Link to comment Share on other sites More sharing options...
cs00bren Posted January 7, 2003 Author Share Posted January 7, 2003 at the moment i'm using L-systems to create the trunk and then using a pop to birth particles from the points and instance a sphere like object to these points. the only thing is the sphere doesn't look that real. i seen a way in lightwave to jitter the sphere e.g. to brake it in to small pieace that look more like leaves any surgestions how to do this in houdini. cheers bren. Quote Link to comment Share on other sites More sharing options...
anakin78z Posted January 7, 2003 Share Posted January 7, 2003 not sure if this is what you meant, but if you make them poly spheres, append a facet sop to make the points unique, and then use a primitive sop, you can rotate and transform each polygon randomly to break up the sphere. use some version of rand($PR) in the transforms, and apply some arbitrary rotation. Breaks it up pretty good. Quote Link to comment Share on other sites More sharing options...
stu Posted January 9, 2003 Share Posted January 9, 2003 Here's a super fast tree that I made using the method I described above. I didn't spend any time on fine tuning the shape, but you can get a sense of it. stu Quote Link to comment Share on other sites More sharing options...
cs00bren Posted January 11, 2003 Author Share Posted January 11, 2003 cheers stu for that the leaves look really good now. the only thing is how do you get the L-System looking like a real tree. at the moment it looks to mathmatical would the easiest way be modifying it with a edit sop or is they a better way e.g. a better rule for the L-systhem. any help would be greatly recieved cheers bren Quote Link to comment Share on other sites More sharing options...
sirogi Posted January 11, 2003 Share Posted January 11, 2003 yup...writing your own rules is what L-systems are all about...it pays to spend a little while figuring out the language..... as a reference and a good (and maybe only) startng point, check out the notoriously scarce book: "the algorithmic beauty of plans" by Przemyslaw Prusinkiewicz (yes, I cheated) and Aristid Lindenmayer (the L behind L-systems) you can also load in some L-sys presets that ship with houdini (the laod prestes button in the params panel onthe L-sys SOP....) check those out for some hands-on examples. have fun (and please no edit SOP ) Quote Link to comment Share on other sites More sharing options...
Jason Posted January 13, 2003 Share Posted January 13, 2003 Sirogi spent a good couple of months stressing over L-Systems during "The Time Machine", so he knows L-Systems, very powerful if you've got your head around them.. until then, it's a useless black box. It just takes some experimentation, but it's fun! Quote Link to comment Share on other sites More sharing options...
sirogi Posted January 13, 2003 Share Posted January 13, 2003 Sirogi spent a good couple of months stressing over L-Systems AARGHH...the...voices...my head......they're backk....NOooo.... L-Systems, very powerful if you've got your head around them.. until then, it's a useless black box amen to that! "getting you head around..." seems to be one of the most painful expression of the english language cheers! Quote Link to comment Share on other sites More sharing options...
cs00bren Posted January 19, 2003 Author Share Posted January 19, 2003 Hello i'm still trying these l-Sysetms getting some really good result. the question is, is there anyway of making the number of rotations / the ne different ever recursion. can you also do it to FFF you us any information would be useful. cheers bren Quote Link to comment Share on other sites More sharing options...
Garman Posted January 20, 2003 Share Posted January 20, 2003 i'm trying to create a landscape scene but i'm having problems with the trees i've tryed l-systems but i've found it to processor intensive. to place them i instances them to a particle system.so the question any good ideas or any tutorials out they. cheers bren. One way to create a unique forest is to create a branch and tree factory. While not a tree, for the brooms in Harry Potter and the Sorcerer's Stone stone I created a branch factory which made some 300-plus different branches. The were variations in my L-systems / SOP setup so that when I played the animation, a different branch was created. One unique branch was written to disk for each frame of animations. After the branches were written to disk, I created a broom factory that read in the bgeo files from disk and combined and bent the branches into the various broom shapes. Writing the geometry to disk help me to keep Houdini from overloading. -Garman Quote Link to comment Share on other sites More sharing options...
cs00bren Posted January 21, 2003 Author Share Posted January 21, 2003 you bring up an interesting point i have tryed exporting the trees as .bgeo and then importing it the only thing is the memory usage is the same. so the question does eporting then importingas a bgeo file speed up rendering time. do you also have any suggestions what i can do with my tree to make it look better and anyway i can in crease render time as i have 500 hundred trees in the scene. cheers bren. Quote Link to comment Share on other sites More sharing options...
michael Posted January 22, 2003 Share Posted January 22, 2003 there was a tutorial around...can't find it now, maybe when I get home...of doing a field of grass is small tiles, then comping them back into the image....never tried it myself but IIRC it could help you with your trees... found it: tiled grass tutorial HTH Quote Link to comment Share on other sites More sharing options...
AndrewVK Posted January 22, 2003 Share Posted January 22, 2003 5 diferent curves (saved Geo in "Bounded File(BBox from render SOP)" mode) were instanced by particle system (100000 particles) Render time (with raytraced shadows) : 6 min. Quote Link to comment Share on other sites More sharing options...
Jason Posted January 22, 2003 Share Posted January 22, 2003 Nice, andrew. You can actually produce some quite nice looking grass just by making the root point of the grass spline dark (or black) in the point attributes. This give the feeling that the root is in shadow and you won't have to cast shadows (which is slow and may alias). Quote Link to comment Share on other sites More sharing options...
cs00bren Posted January 22, 2003 Author Share Posted January 22, 2003 cheers arctor that files a really big help i will give it a go and see what happens. AndrewVK i look though the interface i can see were you can call a Bounded File(BBox from render SOP) but how do you save a geo to one. or am i getting confused and i should just save it as a bgeo file as nomal. cheers ever one the scenes coming on nicely i will put more shots on there latter then the whole things come on a bit. bren Quote Link to comment Share on other sites More sharing options...
AndrewVK Posted January 23, 2003 Share Posted January 23, 2003 Thanks Jason! It is much faster and the result is even better:) 2 cs00bren: Look for attached test scene. I hope it's not to complicated. You can make different animations for any of 5 curves (Bend Sop...Lattice Sop...Point Sop...Vex Sop...CHOPs) and later save them as a sequence of geo (bgeo) files using Geometry ROP. Also you can assign different length, width, color for these curves. I have used VEX Clay as a shader for grass, but it is not so good idea. Cause primitive's normals are oriented perpendicular to camera (if the point attribute "orient" is not set). The same shader is assigned to all curves and surface. However curve primitives have Point attribute "diff" (set by VEX SOP), while Vex Clay shader's parameter responsible for color has the same name, then each curve primitive use it's own color. At the same time, surface does not have this attribure, therefore it uses the color set in SHOP. DelayedRead.zip Quote Link to comment Share on other sites More sharing options...
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