Comments on: Nori: an educational ray tracer

By: Wenzel Jakob

Wenzel Jakob — Sun, 28 Dec 2014 02:16:08 +0000

Hi Frederico,

if you’re still having issues, I’d try reinstalling OpenEXR — maybe after a brew update, you have incompatible .dylib and header files installed on your system?

Wenzel

By: Federico

Federico — Sun, 28 Dec 2014 01:47:02 +0000

To solve for “vtable for NoriWindow”, referenced from:
NoriWindow::NoriWindow(nori::ImageBlock const*) in gui.o

in the .pro file instead of having the line HEADERS += include/nori/*.h, I actually expanded the value of the variable with all the .h files, don’t know if I should modify some settings in order to make the original statement to work.

By: Federico

Federico — Sun, 28 Dec 2014 00:17:38 +0000

I was trying to compile the latest version from github on OS X Yosemite, everything was going good until this error appeared

Undefined symbols for architecture x86_64:
“Imf_2_2::TypedAttribute::readValueFrom(Imf_2_2::IStream&, int, int)”, referenced from:
vtable for Imf_2_2::TypedAttribute in bitmap.o
“Imf_2_2::TypedAttribute::staticTypeName()”, referenced from:
Imf_2_2::TypedAttribute::typeName() const in bitmap.o
“Imf_2_2::TypedAttribute::writeValueTo(Imf_2_2::OStream&, int) const”, referenced from:
vtable for Imf_2_2::TypedAttribute in bitmap.o
“vtable for NoriWindow”, referenced from:
NoriWindow::NoriWindow(nori::ImageBlock const*) in gui.o
NOTE: a missing vtable usually means the first non-inline virtual member function has no definition.
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
make: *** [nori] Error 1
01:16:10: Le processus “/usr/bin/make” s’est terminé avec le code 2.
Erreur lors de la compilation/déploiement du projet nori (kit : Desktop Qt 5.3 clang 64bit)
When executing step “Make”

Don’t know how to proceed with that, I have installed OpenEXR but perhaps I missed something. Any advise?

By: Guo

Guo — Mon, 08 Oct 2012 15:38:10 +0000

Oops, I forgot that it is cosine weighted hemisphere importance sampling, so here one is necessary. Sorry for my hasty comment.
Thanks again for your elegantly designed nori render. 😉

By: Wenzel Jakob

Wenzel Jakob — Mon, 08 Oct 2012 14:52:57 +0000

Hi,

I think you can use Mitsuba as a reference. I can only share the solutions with other course instructors — sorry!

Wenzel

By: Wenzel Jakob

Wenzel Jakob — Mon, 08 Oct 2012 14:50:42 +0000

Hi,

the ambient occlusion integrator computes the occlusion, which is between 1 and 0. You could just as well multiply that by INV_PI, and then it will be in [0, 1/pi] :).

Regarding the inverse transpose transformation: that’s actually what is done if you look at how the Transform operator* is implemented for Normals.

Cheers,
Wenzel

By: Guo

Guo — Mon, 08 Oct 2012 13:39:00 +0000

BTW, I have two stupid questions:
In ao.cpp line 57,
return Color3f(scene->rayIntersect(shadowRay) ? 0.0f : 1.0f);
why not return INV_PI instead of one for energy conservation while the shadow ray is not occluded?
In obj.cpp line 73,
n = (trafo * n).normalized();
why not multiply those normals by inverse transpose of trafo, just like gl_NormalMatrix in GLSL?
Thanks in advance.

By: Guo

Guo — Mon, 08 Oct 2012 12:50:57 +0000

Hi,
I am playing with your cute nori render and doing assignments. Can sample solutions to those assignments be made public? Or Mitsuba render is already excellent for reference?
Regards,
Guo

By: Sam

Sam — Thu, 20 Sep 2012 03:53:37 +0000

Thank you very much!

By: Wenzel Jakob

Wenzel Jakob — Thu, 20 Sep 2012 03:49:01 +0000

Right .. that is the “homework” to do :). There is no path tracer yet, you have to write it. There is an ambient occlusion renderer (“ao”) that you can use to get at least some kind of image. The *ao.xml scenes should work with that.

Note that you have to start Nori from within the directory of your scene, so something like

../../nori some_scene.xml

By: Sam

Sam — Thu, 20 Sep 2012 03:47:16 +0000

Thanks for the quick reply – I reinstalled OpenEXR and now the build completes. However, when I try to run Nori ($./nori ./scenes/cbox/cbox.xml) or any of the other examples I get a “Caught a critical exception: A constructor for class ‘path’ could not be found!”

By: Wenzel Jakob

Wenzel Jakob — Thu, 20 Sep 2012 03:20:21 +0000

Hi,

for some reason, the OpenEXR include files are not found (in particular, “ImathPlatform.h”). Are you sure that you fully installed this (i.e. “make install”) so that the header files ended up in /usr/include or /usr/local/include?

Wenzel

By: Sam

Sam — Thu, 20 Sep 2012 03:18:18 +0000

I was trying to install Nori for educational reasons and received this error when running make from the Nori directory, any thoughts? I am compiling on Mac OS X 10.6.8 and installed the required libraries before running qmake and make.

In file included from include/nori/color.h:22,
from include/nori/proplist.h:22,
from include/nori/object.h:22,
from src/common.cpp:1:
include/nori/common.h:38:27: error: ImathPlatform.h: No such file or directory
include/Eigen/src/LU/arch/Inverse_SSE.h: In static member function ‘static void Eigen::internal::compute_inverse_size4::run(const MatrixType&, ResultType&) [with MatrixType = Eigen::Matrix, ResultType = Eigen::Matrix]’:
include/Eigen/src/LU/Inverse.h:305: instantiated from ‘void Eigen::internal::inverse_impl::evalTo(Dest&) const [with Dest = Eigen::Matrix, MatrixType = Eigen::Matrix]’
include/Eigen/src/Core/ReturnByValue.h:74: instantiated from ‘void Eigen::ReturnByValue::evalTo(Dest&) const [with Dest = Eigen::Matrix, Derived = Eigen::internal::inverse_impl]’
include/Eigen/src/Core/Matrix.h:309: instantiated from ‘Eigen::Matrix::Matrix(const Eigen::ReturnByValue&) [with OtherDerived = Eigen::internal::inverse_impl, _Scalar = float, int _Rows = 4, int _Cols = 4, int _Options = 0, int _MaxRows = 4, int _MaxCols = 4]’
src/common.cpp:72: instantiated from here
include/Eigen/src/LU/arch/Inverse_SSE.h:153: warning: dereferencing type-punned pointer will break strict-aliasing rules
make: *** [build/common.o] Error 1

By: Aurosutru

Aurosutru — Fri, 30 Mar 2012 11:12:54 +0000

Hi Bob,

To compile Mitsuba on Ubuntu pls see the tips at https://www.mitsuba-renderer.org/tracker/issues/83. It’s not hard to build – just download the dependencies indicated in the Mitsuba .pdf manual, making the adjustments indicated above, and build.

If you’re using Blender you can use the interface in the Mitsuba folder created by the build process. Unfortunately, the newer add-ons with more features such as http://bartoszstyperek.wordpress.com/2012/02/19/mitsuba-0-8-just-dof/ don’t seem to work with Linux.

By: Sam

Sam — Fri, 30 Mar 2012 02:14:53 +0000

Please don’t quit on Windows 32bit ;__;

By: Wenzel Jakob

Wenzel Jakob — Wed, 28 Mar 2012 18:56:48 +0000

I’m always having a hard time believing that people out there are still using 32 bit.. It must stop, seriously ;). Have you considered upgrading?

By: bob

bob — Wed, 28 Mar 2012 11:47:55 +0000

Hi, congratulations for the beautiful rendering engine.

But… not Ubuntu 32bit – why?

I can’t install Win 32 version it doesn’t work because of dll errors.

Details:

– Downloaded Mitsuba 0.3.0 32bit.zip 02-Sep-2011
– Installed vcredist_2010_sp1_x86 (from folder “Mitsuba 0.3.0″) – does not work
– Installed msvcp100.dll – still does not work

I tried to find relationships with the program Dependency Walker – the result is the image – link:

http://imageshack.us/f/845/mguierror.jpg/

Help me – pls

By: Sam

Sam — Thu, 22 Mar 2012 19:22:28 +0000

wish there was an edit button – Um sorry about the blender plugin thing, just realized you said you can’t work on it in the near future. – But at any rate I can’t wait to see more from Mitsuba.

By: Sam

Sam — Thu, 22 Mar 2012 19:19:28 +0000

Hey! Glad to hear you’re still working on Mitsuba :3 – Hope you can get a blender plugin working soon, I’d love to use this renderer for my projects (requires to much time at the moment to get a scene working). I feel bad though, I wish I could help instead of just plead >.<

– At any rate what are your future plans for Mitsuba in the long run? I could see this renderer getting very popular as long as it gets easier to use.

Oh btw for the plugin for blender I was wondering if you can possibly rename the materials? Just so it can be easier to figure out which one is which. I understand most of them but some required me to play to see what they were. – Just convenience thing for future users.

By: JoseConseco

JoseConseco — Sat, 17 Mar 2012 21:49:12 +0000

MarcoG, if you want to help maybe you could work based on this code:
http://bartoszstyperek.wordpress.com/2012/02/19/mitsuba-0-8-just-dof/

I updated it to work with blender 2.62, but I haven’t tested it with bmesh (I’m not sure if collada works with bmesh… so it may have broken whole plugin). It is quite easy to code so You may give it a try.
Sorry for not uploading it to svn, but I forgot how to use it. I’m bit out of practise 😉