topic Re: C4DtoA Polymesh to Volume Tutorial in Arnold General Rendering Forum

C4DtoA Polymesh to Volume Tutorial

Anonymous — Fri, 24 Nov 2017 12:17:32 GMT

I am trying to follow Lee's tutorial on Polymesh to Volume with C4DtoA. I used a head and get it to render as a volume with the settings reccommended, but when I add an Arnold Volume to the back of the head nothing appears....I am sure this is my inexperience, but do not know why I get nothing with the same shader applied as the tutorial instructs, and this does not allow me to go forward. Thank you for any help,the site will not allow me to attach my .c4d file

Re: C4DtoA Polymesh to Volume Tutorial

lee_griggs — Fri, 24 Nov 2017 13:11:22 GMT

Is the head model a closed surface, otherwise the volume may not render correctly. More info here.

>the site will not allow me to attach my .c4d file

Are you logged in?

Re: C4DtoA Polymesh to Volume Tutorial

Anonymous — Fri, 24 Nov 2017 13:15:58 GMT

The head is not closed but it is rendering fine, when I add the Arnold volume to the back of the head nothing appears...I am logged in, the site seems to want just pictutre files not .c4d

Re: C4DtoA Polymesh to Volume Tutorial

Anonymous — Fri, 24 Nov 2017 13:16:25 GMT

I will get a closed object for the head though

Re: C4DtoA Polymesh to Volume Tutorial

lee_griggs — Fri, 24 Nov 2017 13:17:38 GMT

>The head is not closed but it is rendering fine

As a volume or as a surface? Can you share some images?

Re: C4DtoA Polymesh to Volume Tutorial

Anonymous — Fri, 24 Nov 2017 13:31:47 GMT

I think the head is rendering as a volume....but I am trying this with a sphere now....in you head example is the Arnold Volume object you add a VDB?

Re: C4DtoA Polymesh to Volume Tutorial

Anonymous — Fri, 24 Nov 2017 13:52:38 GMT

Here is a shot of the head...Nowscreen-shot-2017-11-24-at-84416-am.png I see I can get the Volume Sphere or Box to show...so again is your example using a VDB, and what is necessary for that...I have tried to attache a few VDB's I have from somewhere and they do not render...are there special settings? If you are using a VDB is that available somewhere?

Re: C4DtoA Polymesh to Volume Tutorial

lee_griggs — Fri, 24 Nov 2017 14:28:53 GMT

That looks fine. Yes, it uses a VDB. More information about volumes and VDB files with scene files can be found here.

Re: C4DtoA Polymesh to Volume Tutorial

Anonymous — Fri, 24 Nov 2017 14:35:13 GMT

Thank you so much, having never worked with VDB, so I'll try and get back later sometime, thanks again

Re: C4DtoA Polymesh to Volume Tutorial

Anonymous — Fri, 24 Nov 2017 14:35:57 GMT

Just a comment, the tutorial does not mention the VDB or its settings to start so you might want to add that

Re: C4DtoA Polymesh to Volume Tutorial

Anonymous — Sun, 26 Nov 2017 15:54:01 GMT

Hi Lee...got an idea on some of the problems I've been having....now for the latest....there are several (many) cloud vdb's I got from the internet which I can not see their bounding box in the viewing window...is there an easy way to get an idea of their size or to size them so they fit a window? Problem 2, following your Polymesh to Volume, I am lost when it comes to adding the image to the displacement texture...can you take a look at the attached pictures and let me know if I am doing this all wrong? Thank you so much for trying to get me through this

Re: C4DtoA Polymesh to Volume Tutorial

Anonymous — Sun, 26 Nov 2017 18:36:24 GMT

Just figure out the sizing problem, which was not a sizing problem at all, the volume cage would not show at all unless I moved the timeline to frame 5.....crazy but true, then that is fine....sorry to bother you on that one, if you can get me going on mapping the texture I would appreciate it, Thank you

Re: C4DtoA Polymesh to Volume Tutorial

lee_griggs — Mon, 27 Nov 2017 07:38:01 GMT

That is displacement for poly meshes. You need to connect the image to volume_displacement.

Re: C4DtoA Polymesh to Volume Tutorial

Anonymous — Tue, 28 Nov 2017 01:47:20 GMT

Thank you so much...I am definitely more on track now....the latest question concerns the use of the Camera Projection Shader......and the value you use in the Range Output Max......first the Camera Projection.....is the attached picture using the Camera Projection correctly? I can not get the render to look anything like expected.....the example without it is much more promising, but your Tutorial example is drop dead gorgeous......so I really want to know the correct methodology. The

econd question may be totally tied to the above and my misuse...but is the Output max highly dependent on the Texture file? I can't seem to get over a value of 1 or 2 without some of the geometry totally disappearing

Again thank you so much for getting me through this

Re: C4DtoA Polymesh to Volume Tutorial

lee_griggs — Tue, 28 Nov 2017 06:55:59 GMT

That's it! You are pretty much there. It doesn't have to be a Camera projection. You can try different types of projection to see what works best. Just have a go at experimenting with different textures to see what works best. I tried many textures before I found something that worked. The Range shader is really useful for adjusting the look of the volume. You could also try adding a Ramp inbetween to adjust the falloff of the texture between the volume and the head.

Re: C4DtoA Polymesh to Volume Tutorial

Anonymous — Tue, 28 Nov 2017 11:47:13 GMT

IN the example above that I used the camera projection, am I wired right? I could not seem to make that work at all with several textures.....and I take it that the Output Max is different depending on the effect and texture you use?

THank you again

Re: C4DtoA Polymesh to Volume Tutorial

Anonymous — Wed, 29 Nov 2017 12:02:58 GMT

2 things, in this example I had to scale the image to 12 to get close to the size I wanted, but the horizontal lines (textures edges??) appear, any way to eliminate them? And could you please post a picture of the network editor for your example, I can't imagine how you can get to output max in RANGE over .3 or so without losing your geometry...THanks again for all your help

Re: C4DtoA Polymesh to Volume Tutorial

lee_griggs — Wed, 29 Nov 2017 14:08:45 GMT

You can use a UV Transform shader for careful positioning of the texture.

>And could you please post a picture of the network editor for your example,

There is a screengrab at the bottom of the tutorial.

>I can't imagine how you can get to output max in RANGE over .3 or so without losing your geometry.

Yes, you do, but it looks better for it 🙂