[Closed] Grabbing The Material Preview

I’ve got another slightly hacky way of doing it.

Install Kees’s Helium plugin, and you can use the function to get the shader ball as a bitmap value. It’s not quite as good as the real preview but it’s a lot less lines of code than yours

Wow, great! I don’t know why Autodesk doesn’t give access to this part directly. It would be really great to have the option to have our own material preview window inside our scripts/plugins…

Thank you!

Ha, that’s because someone else did the hard work for you, Dave

Good to know that helium can do this too though – thanks.

this will do it

//********************************************************************************************
  // MtlPreviewToBitmap
  
  def_visible_primitive(MtlPreviewToBitmap, "MtlPreviewToBitmap");
  
  Value* MtlPreviewToBitmap_cf(Value** arg_list, int count)
{
	check_arg_count(MtlPreviewToBitmap, 2, count);

	MtlBase* mb = arg_list[0]->to_mtlbase();
	int sz = arg_list[1]->to_int();

	PStamp *ps = mb->CreatePStamp(sz,1);
	if(ps)
	{
		int d = PSDIM(sz);
		int scanw = ByteWidth(d);
		int nb = scanw*d;

		UBYTE *buf = new UBYTE[nb + sizeof(BITMAPINFOHEADER)];
		if(!buf)
			 &undefined;

// get the image data

		ps->GetImage(&buf[sizeof(BITMAPINFOHEADER)]);
		
// and create the header info		
		
		BITMAPINFOHEADER* bih = (BITMAPINFOHEADER*)buf;
		bih->biSize = sizeof(BITMAPINFOHEADER);
		bih->biWidth = d; 
		bih->biHeight = d; 
		bih->biPlanes = 1; 
		bih->biBitCount = 24;
		bih->biCompression = BI_RGB;
		bih->biSizeImage = 0;
		
		Bitmap *map = TheManager->Create((PBITMAPINFO)buf);
		delete [] buf;

		if(map)
		{
			one_typed_value_local(MAXBitMap* mbm);
			vl.mbm = new MAXBitMap();
			vl.mbm->bi.CopyImageInfo(&map->Storage()->bi);
			vl.mbm->bi.SetFirstFrame(0);
			vl.mbm->bi.SetLastFrame(0);
			vl.mbm->bi.SetName("");
			vl.mbm->bi.SetDevice("");
			if(vl.mbm->bi.Type() > BMM_TRUE_64)
				vl.mbm->bi.SetType(BMM_TRUE_64);
			vl.mbm->bm = map;
			return_value(vl.mbm);
		}
	}
	return &undefined;
}

sz = 0 -> 3232
sz = 1-> 8888
sz > 1 -> 24*24

display (MtlPreviewToBitmap (getMeditMaterial 1) 0)	

edited to remove memcpy

Is it possible to do the other way around?
Meaning – sending in a custom bitmap as a ‘material preview’?

The reason why I ask is because in a exporter I’ve been working on for a long time has it’s own ‘preview tab’ in the material, which then shows the external rendered preview image.
It would be very nice to send that image back into the material slot directly instead.

The exporter calls on a external renderer, that’s why it works with the current setup – we render a preview scene externally, save to a file named the same as material, then when you open that material in the editor it just shows that image.

yes but I think it would need a custom mtl plugin which overides the mtlbase pstamp routines.

it might be possible without the use of a custom mtl, as the PStamp object has a setimage method.

very nice! could you post it on “useful mxs extensions” thread, please?

Thank you guys for sharing this.

@Pete:
There is a action that opens the preview (“Magnify”) window. Perhaps you may want to check it out and see if that could replace the double click hack?

actionMan.executeAction 2 "40296"

Hi Chaps,

thanks for all your input.

Klunk – For those of us not clear about how to approach the SDK, is this method easily usable? My limit is that I’ve built an SDK maxscript extension before, is this a case of adding this and re-compiling? Many thanks for your solution

PolyTools3d – Thanks a million, anything to remove some of my hacky steps is awesome, I’ll change the code and update the article, I’m sure that will work much better.