All posts related to V2
#385772
Hello,

I have a material which is 8 X 8 pavers in two versions 2048 pixels and 4096 pixels. they are meant to cover 1,36 M square at scale.

can you tell me how dense I need to mesh the surface of the geometry in order for the displacment map to function well but also keep render times reasonable? I thought 4 X 4 centimeter square mech should do it... but i am not sure.
The displacement map is subdivided by 6, pretesselated and not smoothed.

the displacement map is not detailed beyond just having the cement joints about 1 cm lower than the pavers. here is the displacement map I made,with a little 'flou' to round off the edge of the pavers and not make them look too sharp at tehir edges:

Image

thanks!

Peter

PS: I think I need to find a good training session.. any ideas? somewhere in europe..; spain france, UK..
#385773
Well with pretesselated, the geometry is simply subdivided and voxelised, so as long as it fits in your RAM when rendering it doesn't matter. Render speed itself won't be affected with pretesselated displacement. It's as if you had that geometry in your scene already subdivided. Of course you do win a little if you subdivide it your self first, so that the pretesselation stage takes a little less time but that is really a trivial gain. The situation changes a lot if you use on the fly displacement which will take a lot longer to render because it's subdivided on the fly, and it will take a lot longer especially if you have deep displacements. On the fly is suited to extremely fine and small displacements, in which case it can be almost as fast as pretesselated with the advantage of course that it doesn't matter how little RAM you have - on the fly doesn't need more RAM.

Also since V2.7 it's supported to have instances with displacement, so go ahead and raise the pretesselation step until you have what you consider enough detail on your "test plane". Be a bit careful though, don't go suddenly from 6 to 60 of course. Then you can instance this plane in case you need to make a path or similar. Saves on voxelisation time and of course you can render the scene since only the first plane will be kept in RAM.

PS: I think I need to find a good training session.. any ideas? somewhere in europe..; spain france, UK..
Would somewhere in Paris, this month be OK? :)

http://forum.maxwellrender.fr/viewtopic.php?f=1&t=4225
#385774
Thanks Mihai,

so you are saying?:

DO NOT use on the fly

Do use pre-tesselated setting.

Does pretesselated mean that I am t"elling the materlial that I have meshed the surface"?

Mesh the object but use subdivison to get the detail?

It just took me an hour an 20 minutes to create just the MXS with these ground blocks meshed at 4 cm X 4cm...

Is this because of the huge number of facettes due to the meshing?
Then you can instance this plane in case you need to make a path or similar. Saves on voxelisation time and of course you can render the scene since only the first plane will be kept in RAM.
I don't understand what instancing is...nor ofr tht matter what you mean by a path

I have been tweaking and testing for 3 days- I find it very hard to learn this stuff- even with the Maxwell documentation.

I am almost ready to forget having displacement on my ground since deadline is Monday...

Thanks

running 2 i7-2600 @ 3,4 ghz 16,0 Goeach.. Windows 7 64 bit.
#385775
Displacement subdivides your geometry before sending it to render.

Ex. you have a single poly plane (made up of two triangles), you set the subdivision steps to 1 in the displacement component = your plane will now have 4 triangles (which is what the render engine receives).

You set the steps to 2 = your plane will now have 8 triangles. Steps to 3 = 16 triangles etc.

You have two options:
1. subdivide the geometry in your modeling app and then use a lesser subdivision step in the displacement component, or even set the subdivision to 0.
2. have a low poly geometry and use a higher subdivision step in the displacement component to subdivide it.

RESULT = you will have the same nr of triangles finally, which are then used to displace the triangles up or down depending on your displacement map.

With pretesselated displacement whichever option you choose has no influence on render time. The only thing that makes option 2 more practical is that you will have a lighter scene to work with, you can navigate in the viewport faster, your scene and the MXS will be smaller since it stores less geometry etc.
It just took me an hour an 20 minutes to create just the MXS with these ground blocks meshed at 4 cm X 4cm...
I'm not sure what you mean by this but if you understand what I wrote above, then I don't think your approach matters. You have a plane, doesn't matter what size it is -> you subdivide it a number of times, enough so that your displacement map can "work" at a given camera distance from it, and a given render resolution and not give you too big displaced triangles that show up in the render. You subdivide enough until they are so small, they won't be visible in your render and you'll have "enough" subdivision for that particular render resolution. Hence there is no exact subdivision number that can be given because it depends not on the size of your plane in your scene, but how much space it takes up in the render itself (how close it is to camera) and how big your render resolution is. A plane that's 10cm from the camera at a render rez of 10 000 px will of course require much higher subdivision in order to "hide" the individual triangles in the mesh, compared to a 1000 px render where your plane is somewhere far in the background and takes up 100 px in the render. Makes sense?

I don't understand what instancing is...nor ofr tht matter what you mean by a path
The info about instances:
http://support.nextlimit.com/display/mxdocsv3/Instances

By path I ment that I don't know if you will have only one of these subdivided planes in your scene, or if they will be repeated along a path, to create something like: http://www.paversearch.com/images/portf ... ones04.jpg

Lets say if you need to create a path visible for 1km, you will need 500 of these planes put one after the other. Each one when subdivided adequately for displacement needs 3 million triangles. No way you will fit that geometry in RAM while rendering if you have even 24GB of RAM. So in that case instances are the only way to go. Or, you would use on the fly displacement but that will be much slower in rendering.
#385776
Hi Mihai,

Ok this is clearer to me now.

I guess if there are two ways to control the number of faccettes being produced-

1.) meshing the surface in my program(formZ)
2.) adding subdivision in the displacement map parameter

I guess the question then is the total of meshes produced what controls how long it takes the MXS to be prepared(the 1 hour 20 min of my last post)?

I was using only 6 subdivisions- now I am testing with 20 subdivisions, but the mesh i apply to the surface is less dense- I am hoping to find the magic combo to give me what I need but not wait an hour just between when I hit CMD "M" and when the Network actually starts to render.

In creasing the subdivision immediately gives better results - I just hope it wont affect the the (?voxellisation) time problem I have mentioned.

I need to do at least one more full test render tonight and I can't afford that much time every test render.

Instancing..DUH! .. I now realize what you meant: basically they are called symbols in FormZ and in the Maxwell parameter there is an option to creat Maxwell Instances from formZ symbols, so that could be useful. The forms of my current project are a bit irregular in plan, though, so making one instance and repeating it to 'fill' may be tricky. But is that what you meant?

I am supposing that you are a moderator on the website- I really appreciate the help!

best regards,

Peter
#385807
1h 20min just for the voxelisation stage?? No that's not normal.

I would try and make a test just with the objects in your scene that are displaced and see. You can also run a test with Displacement off in the render options which will turn off all displacement components, to see if the voxelisation time comes from any displacement component. If it does, I think you have somewhere in your scene some parts which are very heavily displaced for the vox to take such a long time. What is your RAM usage at the end of the voxelisation?
#385818
Hi,

Ok so i got rid of the voxellisation time problem. My sense is that when using a displacement function, the mapping must be perfectly aligned. In my first attemps I had a VERY slightly tilted ground plane, but I had not mapped to this subtle tilt.

Would that have cause a problem?

I am creating instances which I then repeat to strategically create the forground in high res displacement, then I go with no displace further off.This has helped a lot also.

Where do i check RAM usage?

Other question: I am also applying a grass modifier to some geometry. Everytime I must re-enter all the parameters(there are a lot!).

Is there any way to SAVE these grass parameters and re-use-? Also to copy paste them for between different objects I I apply it to in Maxwell Studio!

Thanks-
Peter
#385827
Perfectly aligned? I'm not sure what you mean.....displacement doesn't mean that the geometry can't have any rotations. Something to do with the UV mapping you mean? You are using Planar mapping and this UV plane was not perfectly aligned with your geometry?

Starting with Maxwell 3 you can create presets of grass and that preset will appear in the dropdown at the top of the Grass UI. You can see it already has some presets in that dropdown. Browse to: C:\Program Files\Next Limit\Maxwell 3\extensions\presets

Open the file MaxwellGrass.xpr in any text editor and you can see the structure and settings of this preset file. Add as many presets as you like, following the same structure to this file. Close and reopen Studio for the changes to be reloaded.

For the RAM usage, you can check using the Task Manager in Windows (Ctrl + Shift + Esc).
#385831
hi,

Well I mean by 'perfectly aligned' that my geometry is slightly rotated, but my mapping may not have been, as you can see in this sc from formZ texture mapping interface:

Image

The mapping 'type' selected here is cubic' (but other choiced exist: "flat, spherique, cylinder, parametric and UV coordinates"

I don't have a good understanging of of UV and triangles, etc...

I guess it's time to upgrade to V3- but that will require me to leave FormZ v6(very old) which I have not been comfortable with, but perhaps I could open in Maxwell v3 an MXS produced by in Maxwell v2?
#385842
If it's a flat plane, then cubic or planar UV mapping won't matter, but yes the UVs have to be aligned properly with the geometry.

Maxwell 2 scenes will open in V3, but not the other way around.

Some info about UV mapping:
http://support.nextlimit.com/display/mx ... +in+Studio
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