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Real Camera/Lens simulation - 6mm 220degree Fisheye
Yeah i found HDRshop _ and the light gen plugin really useful -- Has brought a new feel to much of my work... Will definately give that a try + will let u know if i solve it... cheers again, pete.w
From: steven ong <steve_nong(a)yahoo.com> Reply-To: sidefx-houdini-list(a)sidefx.com To: sidefx-houdini-list(a)sidefx.com Subject: Re: Real Camera/Lens simulation - 6mm 220degree Fisheye Date: Tue, 13 Nov 2001 17:37:58 +0800 MIME-Version: 1.0 Received: from [184.108.40.206] by hotmail.com (3.2) with ESMTP id MHotMailBDBA391B009640043148CC5CEAC1737D0; Tue, 13 Nov 2001 01:56:00 -0800 Received: from LocalHostby mail.sidefx.com (Smail-220.127.116.11 2000-Feb-17 #3; 2000-May-9)(5328 bytes) via sendmail with /P:stdio/D:aliasinclude/R:inet_hosts/T:smtpid <m163a2O-004Oz1b(a)mail.sidefx.com>(sender <owner-sidefx-houdini-list(a)sidefx.com>)for sidefx-houdini-list-outgoing; Tue, 13 Nov 2001 04:39:24 -0500 (EST) Received: from northgate.starhub.net.sg (northgate.starhub.net.sg[18.104.22.168])by mail.sidefx.com (Smail-22.214.171.124 2000-Feb-17 #3; 2000-May-9)(4924 bytes) via sendmail with /P:esmtp/D:aliases/T:pipeid <m163a2J-004OyuC(a)mail.sidefx.com>(sender <steve_nong(a)yahoo.com>)for <sidefx-houdini-list(a)sidefx.com>; Tue, 13 Nov 2001 04:39:19 -0500 (EST) Received: from yahoo.com (mcns102.docsis118.singa.pore.net [126.96.36.199])by northgate.starhub.net.sg (8.12.1/8.12.1) with ESMTP id fAD9cnNl018897for <sidefx-houdini-list(a)sidefx.com>; Tue, 13 Nov 2001 17:38:49 +0800 (SST) From owner-sidefx-houdini-list(a)sidefx.com Tue, 13 Nov 2001 01:56:59 -0800 Message-ID: <3BF0E9F6.48063B8(a)yahoo.com> X-Mailer: Mozilla 4.78 [en] (WinNT; U) X-Accept-Language: en References: <F134JopqlqxoUIL2fRO0000e3af(a)hotmail.com> Sender: owner-sidefx-houdini-list(a)sidefx.com Precedence: bulk Hi Pete, > the demos are useful to some extent, but they unfortunately use specially > constructed maps which seem to work from a kind of linear skewing -- i can > see how these can take in a 360 degree environment etc. and then are mapped > around a sphere for projection -- but the virtual camera which i'm using to > make the texture is simply creating an image that is distorted from the > centre (if that makes any sense). I guess the object of the exercise is to > get the stretching of the dome to compensate for the 'compressing' at he > edge of the image. But maybe that is only the case for an orthographic > projection. :) > It's a bit frustrating as i feel this experiment shouldn't be quite so > difficult.. i guess it'll all fall into place eventually... Using CG to simulate reality isn't always easy. ;) Get at it & it'll come to you eventually. I would like to suggest visiting Paul Debevec's website (http://www.debevec.org). Those mirror ball images are very similar to what you're trying to achieve. Also check out HDR Shop (http://www.debevec.org/HDRShop/) which might help you in transforming the images. Cheers! steven > > > Basically what i'm trying to do is make a simulation of a setup where a > >real > > > lens of this kind is used to film live action + the result is later > > > projected from multiple angles onto a real dome which presents the same > > > viewing angle. (The audience end up with a kind of VR view). This rig > >has > > > been used a by a couple of people around the world for exhibitions etc. > >but > > > i'm basically trying to understand more about the > > > concave/convex/curvature/cropping workflow that would be entailed. > > > > > > I haven't spent that long on this really, but i'm looking to find a > >better > > > way to texture the inside of this dome. - At the moment i've got some > > > hideous stretching. (The texture references a COP rendered from the > > > wide-lens virtual camera in my virtual scene nearby. > > > example; > > > www.leperisland.co.uk/poto/petewallace/30mins&2cofeeslater.jpg > > > (short collage) > > > >Look at the demo files that came with Houdini. Go to 'where it's > >installed'\demo\Projects\render\mantra\Panoramic folder & look through > >the examples there. The Projection types that should help you are Polar > >& Cyclindrical. > > > >I hope the above helps! > > > >Cheers! > >steven > > > > > > > >Hi Pete, > > > > > > > > > Has anyone come across any formulas or conversion tables for > >altering > > > > > Focal/Length + Aperture etc. to accomodate the stats of real lenses? > > > > > > > > > > I'm trying to create a virtual camera that emulates a setup i know > > > >exists - > > > > > which uses a 220 degree 6mm Nicon lens. > > > > > > > >How's it going? I think this link should help you a lot: > > > >http://odforce.net/tips/realcam.htm > > > > > > > >This link should help too: > > > > > >http://cade.scope.edu/cadestuff/bascourse/notes/houdini/details/integrate.html > > > > > > > > > Should i be using the lens-curvature camera setting too? (Daft > >question > > > >i > > > > > know - but i'm not sure what ratios of each variable i should be > >working > > > > > in). + it seems that setting doesn't display until rendertime under > > > >Mantra. > > > > > > > >It all depends on what you're trying to do. If your CG elements is > >small > > > >& centralized in the frame, you might be able to get away with it. If > > > >it's a full CG scene, please do. > > > > > > > >As for the curvature setting, others on the list might know better than > > > >me. However, you can use a grid(wren or width attribute) to quickly > >test > > > >values. On the other hand, if there's no real life element to > >reference, > > > >isn't it up to you? > > > > > > > >Cheers! > > > >steven > > > > > > _________________________________________________________________ > > > Get your FREE download of MSN Explorer at > >http://explorer.msn.com/intl.asp > > _________________________________________________________________ > Get your FREE download of MSN Explorer at http://explorer.msn.com/intl.asp_________________________________________________________________ Get your FREE download of MSN Explorer at http://explorer.msn.com/intl.asp
New subject: lens curvature = grainy image
Hi, I'm trying to use a lens curvature when rendering, and as soon as I set it above 0 the resulting image becomes hard and somewhat noisy, i.e. as if the dither went a little while, you can really notice it by comparing alphas between an image rendered with curvature and one without. the one without has a smooth motion blurred alpha, while the one with has a very extreme black/white noise (you get black and dk grey pixs on white areas but not viceversa, so it's a multiplication somewhere). did anyone here looked at lens curvature before and knows the right way to apply it? thanks! dani