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Modelling rubber chain tread #43903 - Printable Version

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Modelling rubber chain tread #43903 - Roland Dahl - 2015-01-28


actually I am working on 70814 Emmet's Construct-o-Mech using SR3D.

For modelling the rubber chain tread (#43903, GreaseBand 151Mm X 2m) I manually repositioned the component parts of this chain tread to get close to the required shape. As I am not fully happy with the result (see image) and my way of modelling I wonder if there is a more comfortable way to generate this rubber chain tread? Is there any LDraw tool which generates a nicely shaped custom chain tread #43903?

From my understanding Lsynth offers only the “technic (rubber) chain tread”. Rubber tread #43903 is not included.

Thanks for advice!


[Image: chain.jpg]

Re: Modelling rubber chain tread #43903 - Philippe Hurbain - 2015-01-28

Lsynth results are not better (by far): see http://jc-tchang.philohome.com/manuel/Lsynth3.htm#ls_type_ttt
Honestly your gease band looks quite good, but maybe if you share your LDraw file we can make something better? (not sure!!!)

Re: Modelling rubber chain tread #43903 - Roland Dahl - 2015-01-28

I agree: The Lsynth rubber tread looks worse.

Thanks a lot for offering help. But I dont wish to further bother you, as now I am very happy with my result!

One more question: My version of Lsynth does not contain #30c TECHNIC_TREAD_THIN which was used by JC-Tchang. Is this something like a "selfmade" feature? Or do I have to do upgrade my installation?

kind regards

Re: Modelling rubber chain tread #43903 - Steffen - 2015-01-29

I like the look of your rendered rubber material.
Could you share its material definition here maybe?
Or your overall lighting setup?

Re: Modelling rubber chain tread #43903 - Philippe Hurbain - 2015-01-29

Yes, it's a custom extension to LSynth definition file, made by LDraw part author JC-Tchang. You can download all the files in his lsynth page here http://jc-tchang.philohome.com/manuel/Images_LSynth3/lsynth3_exemple.zip (and I suggest that you read this page too through a language translator http://jc-tchang.philohome.com/manuel/Lsynth3.htm)!

Re: Modelling rubber chain tread #43903 - Roland Dahl - 2015-01-29

Many thanks for your answer as well as for the links!

Re: Modelling rubber chain tread #43903 - Roland Dahl - 2015-01-29

Hi Steffen,
here are the rubber definitions I used for this render:

#declare lg_rubber_finish =
finish {
ambient 0
diffuse 0.5 // Default is 1
phong 0.5
phong_size 20
reflection 0

#declare lg_rubber_normal =
normal {
bumps 0.1
scale 0.1
turbulence 0

#declare lg_rubber_black = texture {
pigment { color srgb <33/255, 33/255, 33/255> }
finish { lg_rubber_finish }
normal { lg_rubber_normal }

But these are more or less default values as specified by the lgeo-library (see lg_color.inc). The only variation I did is to reduce diffuse from 1 to 0.5.

Regarding lighting I usually use an horizontal area light as a main light:

light_source { <-4000,-6000,-4000> color rgb 1 area_light <8000,0,0>, <0,0,8000>, 8, 8 adaptive 1 jitter circular orient

Sometimes I add vertical area lights too, mainly for getting a better general illumination of the model respectively for enlighting dark areas:

light_source { <-2000,0,0> color rgb 0.3 area_light <2000,0,0>, <0,-2000,>, 6, 6 adaptive 1 jitter circular orient } (or similar)

Sometimes I add a simple light source at camera position, mainly for getting rid of strange render artefacts :
light_source { LDXCameraLoc color rgb .5 }

You can see these artefacts when you have a close look to the yellow wheels.The surface is not uniformly rendered: There are some dark and bright areas side by side.

But for the quick render above I only used an horizontal area light.

Last year I prepared a short tutorial about lighting. You will find some more information about my render settings inside.

Please feel free to ask again. Glad when I can help.


Re: Modelling rubber chain tread #43903 - Steffen - 2015-02-02

thank you very much!