Materials file sizes

[edgardo]

Ron:

 

In Acad 2010, I converted a textured AR4 material to NXT and the resulting new file was 30KB.

 

The original material was created in AR4 using a JPG from Arroway textures.

 

When this material was used in a simple drawing with an slab the dwg file increased the size from 71KB to 132KB, but when,  in a plain copy of the same drawing (without any material) I created a textured material using the same JPG, the resulting NXT material was 3817KB, and the DWG file grew to 6138KB.

 

The final renders from both did not show any real difference.

 

I tested the same with more complex drawings and the results were huge DWG files.

 

Any idea of how to deal with this and have reasonable material sizes directly in NXT?

 

I am using a licensed NXT  v 1.0.237.

 

Thanks.

 

[Roy Hirshkowitz]

Arroway textures are generally very hi-resolution. For most applications this is a waste. We (and Arroway) usually recommend sampling these down substantially using Photoshop (or eq.) and using the sampled down map to create your material. Generally, 1 million pixels is more than adequate for a texture map (you can often get by with even smaller maps.)

My guess is that you did sample the bitmap down when you prepared the original ar4 material (you may even have used their low-res sample jpg which is often adequate). I can check the size of the map used if you'd like to attach the 30kb file-- that will give you an indication of what size map might be appropriate for your application.

[edgardo]

I used the same map (attached) for both ar4 and nxt material.
I actually prepared both today because one model I was working with was getting too big.

I have been testing with other maps with same reasults.

See attached:
Adoquin Rosado Viejo-01.ArMaterial (converted from ar4) 34kb
Adoquin Rosado Viejo-02.ArMaterial (prepared nxt material) 539kb

[Roy Hirshkowitz]

The first material (Viejo-01) has a linked texture-- meaning that the texture map is only stored externally. This will result in the smallest possible material and smallest impact on drawing file size. The downside is that neither the drawing nor the material file are portable by themselves-- they need to be accompanied by the bitmap file.

The second example embeds the same bitmap. It takes up somewhat more room but retains portability.

*****

To change the embed status of a texture in a particular material, edit the material, go to the Texture Maps tab, right click on the bitmap, and change the status. Select "Linked" to prevent embedding and have the smallest possible material.

If you really don't like embedding, you can also change nXt's default behavior. Go to the Options DB, Settings tab, and un-check Embed Textures.

*******

Regardless, of what you decide, I do still recommend down-sampling the hi-res textures to an appropriate resolution for your application. Hi-res linked textures, while they do not effect file size, do greatly affect the memory footprint.

[edgardo]

Thanks a lot.