Johnm Posted August 20, 2005 Share Posted August 20, 2005 I would like to be able to draw a perforated sheet of metal bent to a curve of my choice (perforations as say on the face of a mac G 5 tower). I want to end up with a perforated solid object to test the effect of light passing through . I'd be pleased to hear how do you go about achieving this. Jonas Mac G5 dual, OSX10.3 VW&RW 10.5 Quote Link to comment
propstuff Posted August 20, 2005 Share Posted August 20, 2005 if you search for "perforated" you'll find a number of responses to this question. cheers, Quote Link to comment
Kaare Baekgaard Posted August 22, 2005 Share Posted August 22, 2005 Use a texture for perforation. It will allow light to pass through the holes. Quote Link to comment
islandmon Posted August 22, 2005 Share Posted August 22, 2005 Indeed, a perforated mask texture. A simple Image Prop would work as well if the end result is just a limited test of the light penetration. Quote Link to comment
Johnm Posted August 22, 2005 Author Share Posted August 22, 2005 I did as propstuff suggested and found replies to a similar question by Geoffrey P 03-21-04 which I need to digest as I am not too well up on mask transparency etc. Thanks also for the other replies. I would like to progress to taking a thicker sheet say a half inch thick standard sheet of ply with holes drilled at regular intervals and then bent to a curve , how would you model this in VW /RW. Jonas Mac G5 dual 2 OS 10.3 VW/RW 10.5 Quote Link to comment
alanmac Posted August 22, 2005 Share Posted August 22, 2005 The problem is that for what you require you have to perforate the sheet in its curved state and to do this correctly you need to have each hole running parallel to the curved centre of the sheet. It's possible but involves a huge amount of work from what I can see. I've tried perforated sheet using two methods, clip surface then extrude and by subtract soilds method. Both slowed my computer to a crawl, tieing it up for great lengths of time as the calculations for each hole was worked out. I even tried it in stages but the more holes I added the slower the computer ran. This was on flat sheet. I imagine curved sheet would increase the computations considerably. Good luck Alan [ 08-22-2005, 07:56 PM: Message edited by: alanmac ] Quote Link to comment
mike m oz Posted August 23, 2005 Share Posted August 23, 2005 I have used islandmon's method in the past (see above) and it works well. Quote Link to comment
propstuff Posted August 23, 2005 Share Posted August 23, 2005 I have modeled this in the past as Alan has and with the same methods, and had the same result. A file that groaned with the calculations. That's why I used a mask transparency. In short, it's do-able, but slow: you'd want to have a fast computer and a specific reason for doing it. BTW, (as far as I know), you cant make a solid and deform it like that in VW. Concepts Unlimited can, but I don't know if it would work with a perforated solid. good luck. Quote Link to comment
Johnm Posted August 24, 2005 Author Share Posted August 24, 2005 I will check out the method recommended. I enjoy the forum and am always amazed how willing the contibutors are to part with their hard earned knowledge . Long may it continue Thanks to you all. Jonas Mac Quote Link to comment
islandmon Posted August 29, 2005 Share Posted August 29, 2005 One more method... the Fractal Approach: Create a Fractal NURBS Surface symbol of the minimum case which in this instance is a single hole penetration into a slightly curved slice the thickness of the plywood. Then iterate that Fractal symbol to form a composite of the entire surface. It's quick...it's easy ... and it renders relatively fast. Also, of course, it's far simpler to make changes to the single Fractal Symbol... Quote Link to comment
islandmon Posted August 29, 2005 Share Posted August 29, 2005 Check out this Fractal example. FinalQualityRender is really FAST: Fractal_CurvedPerforation VRML (1.8mb) Quote Link to comment
David Ormsby Posted August 29, 2005 Share Posted August 29, 2005 Is this Nurbs Fractal specific to Architect? Quote Link to comment
mike m oz Posted August 29, 2005 Share Posted August 29, 2005 Islandmon - I don't really understand what a fractal is, let alone how to create one, and I am sure I am not Robinson Crusoe. Would it be possible for you to post in plain English the method for achieving what you have displayed above along with an explanation of fractals. Quote Link to comment
islandmon Posted August 30, 2005 Share Posted August 30, 2005 Sure... a Fractal is the simplest possible shape that best represents the required data. In this case a curve surface of certain thickness with an extruded hole punched through it. The Fractal then is the minimum NURBS solid with the extraction of the tapered extruded circlular hole. To keep it simple I just used a 10? arc with radii of 5 & 4.75 and width & depth of 1 to create the NURBS solid for the plywood then I extracted out the 10? tapered cylinder of r=.25 & .2375 and depth = .25. I applied the standard Pine texture to the solid. In the image above the arrow points to the Fractal just described. Then I converted it to a symbol with a 3D Loci at 000. Once the Fractal symbol is set to the center of the GP it is possible to iterate it by duplicate array to create 90 similar stacked solids with holes in them. Rendering time depends only on a single Fractal symbol...so it's instantaneous. Here's a link to the original file for you to check out: Example_CurvedPerforation_VW11_file Quote Link to comment
alanmac Posted August 30, 2005 Share Posted August 30, 2005 The trouble is that perforated sheet does not exactly come like this example. Each row is alternated to have its hole centres offset by 50% of the row above or below it. Guess you could still do it this way but would need to create a shape with a hole in the centre and a quarter circle at each corner, so when duplicated these become complete holes. Wonder how that would work on render times ? Alan Quote Link to comment
islandmon Posted August 30, 2005 Share Posted August 30, 2005 Just offset the Fractals row by row. And then create a solid 1/2 to fill in the end conditions. End of story... Quote Link to comment
islandmon Posted August 30, 2005 Share Posted August 30, 2005 Here's the offset with end Fractals shown as diff texture: Quote Link to comment
mikatoa Posted August 31, 2005 Share Posted August 31, 2005 Can the perforated mask texture method apply to a curved wall with thickness. End can be given a texture too. Just a thought. Quote Link to comment
alanmac Posted August 31, 2005 Share Posted August 31, 2005 quote: Originally posted by islandmon: Just offset the Fractals row by row. And then create a solid 1/2 to fill in the end conditions. End of story... Not quite end of story EJ but that is very good, easy way of thinking. Better if the solid half had half a hole in it to be really accurate and done easily as the other ones you created I'm sure. Must try this method when I've got some time. Well done. Alan Quote Link to comment
islandmon Posted August 31, 2005 Share Posted August 31, 2005 The Fractal method is incredibly powerful as well as conserving resources & processor cycles. Here's an example of a single Fractal NURBS surface sliver 'protein' that makes the complex viral shell possible: A single NURBS Surface Fractal The Viral Shell composed of 120 NURBS Fractals Quote Link to comment
islandmon Posted September 2, 2005 Share Posted September 2, 2005 Couldn't resist posting this 3D NURBS Geodesic built from a single 'negative fractal': Quote Link to comment
APE Design Ctr Posted September 2, 2005 Share Posted September 2, 2005 Thats pretty trippy EJ. Quote Link to comment
bc Posted September 3, 2005 Share Posted September 3, 2005 Islandmon, OK it's time to write the book. Sometimes your answers are at once both painfullly cryptic and intellectually enticing. I am often responding with "so how do I do this" or "how can I learn that?". Produce the esoteric knowledge and they will come. You could title it, "Nurbs and Other CAD Geometry: a Practical Guide in Plain English with step-by-step Instructions for the Average CADmon". I, for one, would buy it. Perhaps there are already some books out there you could refer us to? Quote Link to comment
islandmon Posted September 5, 2005 Share Posted September 5, 2005 bc... mucho gracias for your encouraging comments. FYI for the last 5 years I've been writing and publishing a compilation of the basics of Synergetic Geometry and the Isotropic Vector Matrix including stereo imagery to help explain the concepts. But alas, the project is running too far ahead of the time I have to give to it these days. Thought you might enjoy checking out a Quantum Gravity module. This little sucker exists in a portion of our Universe where a transcendental like pi is simply not required. Here's the link to the 2.5mb Quicktime VRML if you're interested... Quantum Gravity Quote Link to comment
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