VRImage help please.

[Philthy]

I've been following various threads on how to use VRImg2exr and have a few questions.
Sorry to all the admins, etc. for the spam but i'm desperate to get my crashing problems solved when rendering at high res.

I followed the Large Res Tutorial, up to Step 3 (my image is currently rendering to VRimage... is it supposed to rebuild light cache and prepass again? or go straight to rendering?

Also in step 3 it says run the cmd and i have tried all that but it doesn't work, is there another way to get the VRimg2exr to work? and what do i do with the Openexr file. do i put that into the photoshop directory and if so where abouts in that directory (i have PS CS).

Thanks

[dalomar_cg]

Re: VRImage help please.

If you're loading a saved irradiance map and a saved Light map, then the render process will proceed directly to rendering.

As far as converting your VRImage, just right click on the file and choose Open With. The locate the VRImg2EXR executable file. Now, "opening" the vrimage file should automatically convert the file and place the EXR in the same folder as the vrimage. Don't worry about the commandline or any of those options unless you directly need to.

[Philthy]

Re: VRImage help please.

thanks, i think i was neglecting to upload the lighting VRimg. so does VRimg work for all the render engines in the event I needed to use DMC? Does this always work/prevent the crashes because I've had a horrible past few days trying to sort out why it was happening.

[dalomar_cg]

Re: VRImage help please.

Are you talking about a VRimg file or a vrMap file? A VRimg file is basically the raw rendered output and will work with any settings that you have. Basically the VRimage format writes the rendered information to a file bucket by bucket which releases the memory that would normally be used for keeping the image in memory. For large images, the memory needed for the image alone can be significant and releasing that memory can be enough to allow an image to be rendered.

VRMap files are the saved Irradiance map files. These can be saved to be reused for another rendering, but don't actually display any sort of images. They can only be used with the Irradiance Map engine. Using a saved map can save memory as well, since the map can be read from the hard disk if memory is need for other processes.

As far as whats taking up all of you're memory its most likely the geometry of your scene or the images that you're using as tetures.

[Philthy]

Re: VRImage help please.

I am very new to Vray so I'm not quite sure what I'm doing sorry if i'm not making much sense.

I don't seem to understand, I gather that the VRimg file is the final render file which I put into the VRimg2exr? and the VRmaps and VrLmaps, are the files where I save the pre-render process such as Irradiance and Light Cache in step 1 to release memory, and which I use to generate the Final VRimg?

Would rendering straight to VRimg cause crashes, and does that 'bucket' the cache building and prepass stages too or only the raw VRimg file? (ie. avoiding first generating vr/vrlmaps and uploading from that to render).

I notice that many people have what seem to be very detailed interior and exterior scenes. I am very worried that if I try to increase the detail/resolution too much it will cause rhino to crash. May I ask what procedures you generally do to ensure a high quality render without a crash.


Regardless of what render engine, should I always "Render to VRimage" (output rollout), to avoid rhino crashing?

I appreciate the time your taking to help me out, I was really looking forward to using Vray however since I got it I haven't been able to produce a high quality render due to constant crashing during rendering, which is extrememly frustrating.

[Philthy]

Re: VRImage help please.

Bah crashed yet again rendering using IR and LC (but straight to VRimg without saving VRmaps/VRlmaps first.)

How do I get a good render whilst avoiding a crash during prepass stage? Any suggestions for this and my post above this one?

Thanks

[Micha_cg]

Re: VRImage help please.

Maybe you reach the RAM limit of your system - somewhere at the forum are posts to the topic "large scene - RAM - crash - ...".

[dalomar_cg]

Re: VRImage help please.

Check your render mesh settings. Decreasing those might allow you enough head room to get through the rendering. It definitely sounds like you're just running out of memory.

[Philthy]

Re: VRImage help please.

Any thoughts on how to fix the loss of memory?
I am running Rhino v4.0
My system specs:
2.4 GHz Dual Core,
512mb Nvidia 8700m
4GB ram (but only using 3GB due to Vista Home 32-bit)

Should I normally be able to render straight to VRimg without pre-saving the VRmaps?

UPDATE:

I have conceeded that it is indeed a lack of usable RAM that is causing the crashes. Micha you have mentioned in a few places that 32bit-OS stops at 1.6gb RAM usage in Rhino, is this only for XP or is it also for the Vista 32bit-OS. How can I increase my usable RAM, you mentioned something about '3gb switch' (can i do this with vista and rhino v4)? is the only option to buy a 64-bit OS? I hope not as I don't want to be forced to return Vray

[dalomar_cg]

Re: VRImage help please.

the 1.6 gb issue is inherent to any 32-bit OS. Adding the 3gb switch should help and that is an OS modification not something through Rhino.

There are a number of ways to decrease memory usage. The main one is to have a coarser render mesh setting. Because users like to see rendermeshes that are as "refined" as the nurbs they are representing, I would bet that you can have a coarser mesh and it will give you enough headroom to render. The second step is decrease the size of your textures that you're using. Decreasing each dimension of the image by half actually decreases the amount of information by 3/4. So shrinking the textures can really lighten the load (especially if they are really large to begin with). Lastly you can take Micha's approach which involves saving the meshes (and lights) out into a separate file and opening up that file to render. Not having the NURBS data will save on some memory as well.

As far as presaving light maps, I don't believe that it really saves that much ram (maybe a little, but not too significant), but its just a good idea so that you don't have to calculate the information twice if it crashes.

[Philthy]

Re: VRImage help please.

would you be able to direct me to info on how to achieve this 3gb switch and how do i check if it works or not after i make the switch?

I will try the coarser mesh render (is that in the render mesh properties or is that done when you create the mesh from nurbs geo?) and will that have an affect on the final render?

I have tried saving the mesh/lighting without the nurbs in another file and rendering but still get crashes during the prepass stage.

Most textures that I have got that aren't in teh default library are from asgvis.com, how do i go about reducing the texture size?

And what is a good system to achieve high quality renders? Micha mentioned something about 64-bit OS not using more than 3.6? so would a quad core, 4gbram be good enough to render high quality images?

Thanks again for all your help.

[dalomar_cg]

Re: VRImage help please.

http://www.microsoft.com/whdc/system...AE/PAEmem.mspx

[Philthy]

Re: VRImage help please.

After the 3GB switch, how much more RAM from 1.6 will I be able to access?

What is the likely hood of a crash using a single (ie. no other slaves) 64-bit OS with 4gb and quad core?

[Micha_cg]

Re: VRImage help please.

I cant't remember me, how much RAM is available per 3GB switch - did it ever work for Rhino? I don't know. Since a long time I use XP64 and the Rhino crash RAM limit is approx. 3.6GB (5GB or more RAM installed). If 4GB RAM are installed, the crash limit could be 3.2GB. More than 5GB dosn't help to increase the RAM limit for a single task, but help to use more RAM at more than one task.
QuadCore + 8(5)GB RAM + XP64 is a "best solution" for me.

We talk about Rhino 4 or? Rhino3 is limited at 1.6GB in any case, only a patch helps (link posted somwhere at the forum here).

At the Rhino options can be found the general mesh settings for render meshes. Lower mesh setting can cause visible polygons at the rendering. At the object properties can be set object based mesh settings.
At my rendertools is a tool, that show the polycount of the whole scene or selected objects.

Reducing texture size -> use an image software.

Last I rendered a train interior with much geometry and high res output - converting all NURBS to low poly meshes, delete the NURBS from the file and usage of non-highres textures helps me to get a RAM usage below 2GB (that surprised me ).

Downside of 64 OS? Some drivers could be a problem - for example MyBook external HDD dosn't support 64bit. But driver problems are seldomn and alternatives are possible most. I like XP64.

[Philthy]

Re: VRImage help please.

I applied the 3GB switch to my Vista32, and yet it doesn't seem to make any difference. My scene is very small (2.5mb) i've tried meshing, then removing nurbs, yet I still crash at the Prepass stages at a small res 512x384.

My Usage in task manager never went above 1.8 and yet I still crash. This is very annoying and frustrating Is the only solution to buy a new 64bit system?

Desperately need help....

In your experience Micha, have you crashed using the XP64 whilst rendering (without using render slaves?)